Converted mobs always have their rotation set to 0,0 (south) after converting.
Reproduction Steps
Do
/tick freeze
Spawn a piglin
Do
/tick step 300t
Once that's done do
/tick step 1t
Observed Results
The mob loses whatever rotation it had and starts facing south
Expected Results
The mob would keep its rotation data
Linked issues
Attachments
Comments 1

My bad this is a duplicate of MC-248587