Rotobrush crashes AE when adding a stroke

I have a project which crashes AE every time I use the rotobrush, without exception.

Steps to reproduce:
Open the project I’ve previously created a rotobrush shot on (using v.4.0 of the Object Matte effect).

Open the comp, double-click the layer.

Click Freeze to unfreeze...or don’t - it makes no difference whether it’s frozen or not.

Using either the Quick Selection Tool or Selection Brush Tool, draw a stroke - anywhere, it does not matter. Interestingly, the Object Matte tool does not crash AE, but it does not create the effect I want - it selects too much, so I need to use one of the brush tools.

 
Result:

AE crashes, with message:

After Effects (Beta) error: crash occurred while invoking effect plug-in “Roto Brush & Refine Edge”.

Expected:

No crash.
 
System info
    Application: After Effects (Beta) v26.3.0.30
    OS: Windows v10.0.26200, RAM: 127.91 GB GB, CPUs (logical): 32