Occasionally, pages have stray opening table tags which may end up screwing up DSR computations (which in turns messes up selser). It is possible that our latest foster parenting code implicitly handles this by wrapping the entire table as templated and protected a large body of code (which could then serve as a flag to the user to look for bugs in the wikitext souce). So, it might be worth verifying this and adding tests to spec this behavior.
See my response that fixed the problem in the wikitext source: https://en.wikipedia.org/w/index.php?title=Wikipedia:VisualEditor/Feedback&oldid=574483272#References_and_tables
If this is not already handled by our handleUnbalancedTables and markFosteredContent DOM passes, we may need to tackle this -- by maybe adding a fixup in TokenStreamPatcher that enforces limited table scope (section boundaries is the obvious scope limiter => close unclosed tables whenever section heading tokens are encountered).
To be investigated and fixed.