FIX: make get_field_extremum more resilient

[lorenzovecchietti]

Close #5959

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.07%. Comparing base (8239f21) to head (a7e49a3).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5979      +/-   ##
==========================================
+ Coverage   85.06%   85.07%   +0.01%     
==========================================
  Files         163      163              
  Lines       62780    62781       +1     
==========================================
+ Hits        53401    53409       +8     
+ Misses       9379     9372       -7     

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