Near notation issue: TypeError: Cannot read property 'before' of null

[zstone1]

I get a weird error message after completing a near proof, but before Unshelving:

TypeError: Cannot read property 'before' of null

Not sure what it's talking about, and everything works fine anyway. So it seems like a fairly low-priority issue.

For a repro, stepping just before the Unshelve in filter_app will encounter the errs