Rotobrush often gets itself into a state where it is constantly propagating after any alteration

[David2498646303lk]

I've been using rotobrush in after effects for a few months now, so I'm still an absolute beginner but I feel I have got to grips with the basics and have been getting some very satisfactory results. 

I am trying to follow suggested workflows as much as possible, so I am trimming my clips to only the parts that need roto-ing and keeping them short (only a few seconds) and I have the clip being roto'd alone in its own precomp.

A lot of the time it works fine, but sometimes, for reasons I can't put my finger on, the rotobrush tool gets itself into a state where ANYTHING I do with the rotobrush... foreground paint, background paint or change the frame I'm on, causes rotobrush to re-propogate the whole clip from the beginning. It becomes impossible to work with.

I don't *think* I'm doing anything wrong, and I can find examples of other people with the same problem in this forum, but it never seems to be acknowledged as a problem and always implied that it's user error. 

I am 100% open to it being my user error, so my questions are: when this constant propagation happens, what could I try to fix it? Does anyone know for certain something you can do to trigger this behaviour so I can avoid it?

Many thanks. 

[Mylenium]

Without any info about your system, the footage you are working with and so on we can't tell you much. From the footage not being suitable for RB to specific issues with hardware acceleration this could be anything. In the latter case of course check the settings, in particular the decoding option in the Import preferences. Anything more will require better info.

Mylenium

[David2498646303lk]

Thank you. I appreciate you taking the time to leave a reply.