I would assume this occurs for all forms with burrow, but this was with marmot. If you start to burrow, and end up getting attacked by a PC or NPC, you don't stop trying to burrow, and if you succeed, you're immediately brought back out into combat with the lag as well.

You search for a suitable place to dig a burrow.

(373hp 965m 620mv wilderness)
You start digging a burrow to hide yourself in.

(373hp 965m 620mv wilderness)
A knight has arrived.
A knight yells 'a furtive marmot! Now you die!'
A knight's punch EVISCERATES you!
A knight's punch EVISCERATES you!
A knight's punch EVISCERATES you!
A knight has a few scratches.

(256hp 956m 628mv wilderness)
A knight dodges your bite.
A knight dodges your bite.
A knight's punch misses you.
A knight's punch EVISCERATES you!
You sure are BLEEDING!
A knight has a few scratches.

(208hp 956m 628mv wilderness)
You dig deeper underground, creating a deep tunnel.
A knight has a few scratches.

(208hp 956m 628mv wilderness) flee

Hah! I never posted this as Dalgorin assuming it was
part of the price you paid, after the first death to
it I just never burrowed if an enemy was too close.
:)
Just goes to show me that I should post everything
I think might be a bug and just roll with any
"by design" answers eh?

n/t