It seems like sometimes it hallucinates these indentation errors and sometimes they are real and it cant fix them. Happens often for me with python and sonnet-3.7
Im not using python but on the same app version i had issue when my rules were partially contradicting it messed up the code very similar to what you describe. I
First i thought its an Cursor bug but when I changed the rules for other reasons it went away and i realized the cause and could even reproduce it.
fixing the errors, saving a backup (.bak), closing and opening cursor, resulted in 89 problems in the recently corrected code (same 89 errors that I had just fixed) and 8 problems in the .bak file.