[1.4.1b1] Fill for Slice effect in "From To" mode uses its range in a weird way

[b8ck8tt]

1. Create a pattern with length of 10 (hex) / 16 (dec)
2. Fill every other step with a C5
3. Select FX1 column with Shift + Up Arrow, Press Fill
4. Where? - choose "Note", Fx Type - choose "Slice", Fill Type - choose "From-To"
5. From - choose "1", To - choose "8", press "Fill"

Observed Result: Slices are filled with double "1" slice and up to 7.

Expected Result: Slices are filled from 1 up to 8.

Additional Information:
If you choose From 1 To 9, it works in an expected way.
Sometimes From 1 To 8 works correctly, but if you fill with something else, and then try again from 1 to 8, it will fill with double 1s.
Same issue happens if you choose filling from 3 to 10, 4 to 11, etc.

[MortalJS]

Bug confirmed. Transferred to developers.

[Jacknametrouble]

Fixed in firmware v1.5.0