I found a huge bug in the regen function

[xGalardo 13]

Hello! I found an old bug related to regen time.

Example:

A 1m respawn monster appears at 9:20, is killed at 9:20:18, so it will reappear at 9:21.
A 1m respawn monster appears at 9:20, killed at 9:36:45, reappears at 9:37.

How can this be fixed? I would need it to count the respawn time from death.
 

This is what I need:

Example:
If I kill it at 12:20:15, it should appear at 12:21:15.