hasparent returning true if parent is dead

Summary

hasparent returning true if parent is dead

Steps to reproduce

Skill:

Manage-Lava:
  Skills:
  - skill{s=Lava-Message} @Parent
  - remove @self ?!hasparent
Lava-Message:
  Skills:
  - setvariable{var=skill.test;val=<target.name>;t=STRING}
  - message{m="<skill.var.test>"} @PIR{r=40}
  - message{m="has parent - Lava Message"} @PIR{r=40} ?hasparent
  - message{m="has NO parent - Lava Message"} @PIR{r=40} ?!hasparent

Current behavior

With the above skill on the summoned mob, the following will occur when the parent is killed: https://pastebin.com/5PTYTqdn

Intended correct behavior

hasparent should be false when parent is dead.

Server log file

No errors.

Debug log snippet

No errors.

Proposed fixes

check if parent is alive in hasparent