Brush creates mask in bigger areas out of its path

I need to make a mask with a brush, as always, but on a specific photo it has a weird bug, like the brush glitches masking other areas where i'm not drawing. No automatic mask selected, no problems on other photos and i've already tried to close and reopen Lightroom.

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Lightroom 5.5 x64 [ 20220803-1612-16f3c2a ] (Aug 3 2022)

Win 10 Home x64 version 21H2

AMD Ryzen 7 2700 Eight-Core Processor 3.20 GHz

32 GB RAM

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Thanks in advance