Disappearing path markers

(Inkscape 0.91, Windows 7)

Quite often, I have arrowheads (markers) from lines disappear following a copy/paste operation, or shortly thereafter. The correct marker may briefly appear, but then disappear after a half-second or so. Sometimes it gets to the point where I cannot *set* an marker; it appears for a short time, then disappears again. With a little experimenting, I've arrived at the following....

STEPS TO REPRODUCE:

* Open file "bad_arrowheads.svg"
* Select all
* Set right marker to a large arrowhead marker (from the builtin list; 2nd item below the gray divider).
* Copy, New Image, Paste. (should look ok so far)
* Select all
* Set right marker to the 3rd marker below the gray divider
* Markers flash for a while, including a brief change to the correct marker, then all markers disappear.
* After that (in my hands) any marker chosen causes a similar behavior.

"Clean up document" doesn't fix the problem.

Saving files once the behavior triggers, quitting, then re-opening seems to reset whatever is causing the problem so that I can interact normally with the markers again for a while.

It feels like some kind of interaction is happening between marker references in the drawing.

While bugs #165659 and #165479 sound similar, they are (a) for very old versions, and (b) resolved; apparently, this is a novel report.