can't install with zef, test failures

[coke]

$ perl6 --version
This is Rakudo version 2016.12-223-g6d28c1d built on MoarVM version 2016.12-60-g36f3385
implementing Perl 6.c.

$ zef install JSON::Fast;
===> Searching for: JSON::Fast
===> Testing: JSON::Fast:ver('0.7')
t/01-parse.t ...... All 93 subtests passed
t/02-structure.t .. All 10 subtests passed
t/03-unicode.t .... All 4 subtests passed
t/04-roundtrip.t .. ok
All tests successful.

Test Summary Report
-------------------
-------------------
t/01-parse.t  (Wstat: 0 Tests: 75 Failed: 0)
  Parse errors: Tests out of sequence.  Found (13) but expected (12)
                Tests out of sequence.  Found (14) but expected (13)
                Tests out of sequence.  Found (15) but expected (14)
                Tests out of sequence.  Found (16) but expected (15)
                Tests out of sequence.  Found (17) but expected (16)
                Tests out of sequence.  Found (18) but expected (17)
                Tests out of sequence.  Found (19) but expected (18)
                Tests out of sequence.  Found (20) but expected (19)
                Tests out of sequence.  Found (21) but expected (20)
                Tests out of sequence.  Found (22) but expected (21)
                Tests out of sequence.  Found (23) but expected (22)
                Tests out of sequence.  Found (24) but expected (23)
                Tests out of sequence.  Found (25) but expected (24)
                Tests out of sequence.  Found (26) but expected (25)
                Tests out of sequence.  Found (27) but expected (26)
                Tests out of sequence.  Found (28) but expected (27)
                Tests out of sequence.  Found (29) but expected (28)
                Tests out of sequence.  Found (31) but expected (29)
                Tests out of sequence.  Found (34) but expected (30)
                Tests out of sequence.  Found (35) but expected (31)
                Tests out of sequence.  Found (36) but expected (32)
                Tests out of sequence.  Found (37) but expected (33)
                Tests out of sequence.  Found (38) but expected (34)
                Tests out of sequence.  Found (40) but expected (35)
                Tests out of sequence.  Found (41) but expected (36)
                Tests out of sequence.  Found (42) but expected (37)
                Tests out of sequence.  Found (43) but expected (38)
                Tests out of sequence.  Found (44) but expected (39)
                Tests out of sequence.  Found (45) but expected (40)
                Tests out of sequence.  Found (46) but expected (41)
                Tests out of sequence.  Found (47) but expected (42)
                Tests out of sequence.  Found (48) but expected (43)
                Tests out of sequence.  Found (54) but expected (44)
                Tests out of sequence.  Found (55) but expected (45)
                Tests out of sequence.  Found (56) but expected (46)
                Tests out of sequence.  Found (61) but expected (47)
                Tests out of sequence.  Found (62) but expected (48)
                Tests out of sequence.  Found (63) but expected (49)
                Tests out of sequence.  Found (64) but expected (50)
                Tests out of sequence.  Found (65) but expected (51)
                Tests out of sequence.  Found (66) but expected (52)
                Tests out of sequence.  Found (67) but expected (53)
                Tests out of sequence.  Found (68) but expected (54)
                Tests out of sequence.  Found (72) but expected (55)
                Tests out of sequence.  Found (73) but expected (56)
                Tests out of sequence.  Found (74) but expected (57)
                Tests out of sequence.  Found (75) but expected (58)
                Tests out of sequence.  Found (76) but expected (59)
                Tests out of sequence.  Found (77) but expected (60)
                Tests out of sequence.  Found (78) but expected (61)
                Tests out of sequence.  Found (79) but expected (62)
                Tests out of sequence.  Found (81) but expected (63)
                Tests out of sequence.  Found (82) but expected (64)
                Tests out of sequence.  Found (83) but expected (65)
                Tests out of sequence.  Found (84) but expected (66)
                Tests out of sequence.  Found (85) but expected (67)
                Tests out of sequence.  Found (86) but expected (68)
                Tests out of sequence.  Found (87) but expected (69)
                Tests out of sequence.  Found (88) but expected (70)
                Tests out of sequence.  Found (89) but expected (71)
                Tests out of sequence.  Found (90) but expected (72)
                Tests out of sequence.  Found (91) but expected (73)
                Tests out of sequence.  Found (92) but expected (74)
                Tests out of sequence.  Found (93) but expected (75)
                Bad plan.  You planned 93 tests but ran 75.
t/02-structure.t (Wstat: 0 Tests: 7 Failed: 0)
  Parse errors: Tests out of sequence.  Found (8) but expected (6)
                Tests out of sequence.  Found (9) but expected (7)
                Bad plan.  You planned 10 tests but ran 7.
t/03-unicode.t  (Wstat: 0 Tests: 2 Failed: 0)
  Parse errors: Tests out of sequence.  Found (2) but expected (1)
                Tests out of sequence.  Found (4) but expected (2)
                Bad plan.  You planned 4 tests but ran 2.
Files=4, Tests=103,  5 wallclock secs
Result: FAILED

[ugexe]

Upgraded rakudo rakudo/rakudo@b120ac4

[coke]

Verified, worked fine with

$ perl6 --version
This is Rakudo version 2016.12-253-gfbbe446 built on MoarVM version 2016.12-71-g331a6b4
implementing Perl 6.c.