Paste in Markdown hangs

Pasting while editing a Markdown cell hangs sometimes for about 5-10 sec and more (up to a minute). This only affects copy/pastes from the same cell, pastes from other cells or another app work well. The hang is accompanied by a small rotating indicator
For the text to be pasted the cursor should not be moved; moving the cursor results in no text pasted. The effect is intermittent, couldn’t find a pattern.