[RndTbl] git subtree push suddenly got very slow?

[Trevor Cordes]

All of a sudden about a month ago git subtree push from one local repo to
another local repo got very slow.  (Note: "subtree".)  Like 90 secs
instead of maybe 15s.

Anyone else have this?  Any solutions or chatter?  I couldn't find
anything except years-old chatter, which doesn't seem to apply.  This
feels like a new thing/bug, not a "I hit a weird corner case".