Index error in 8c Location Tracking_individual

[liiiiseh]

Hi everyone,
In cell 8c I sometimes get this index error.
I don't know why as all my videos are supposed to be the same (same arena used for all my animals), the length of the test is always defined in cell 2 but for some reason sometimes I do get the error and sometimes I don't.
I am adding 3 regions of interest in cell 6 but again, I'm trying to make them all look the same between videos so I'm not sure that this error is coming from this cell either. Do you have any idea of what could cause that and how I could debug the code ?
Thank you !