Axolotl's despawn after players leave area

What I expected to happen was...:
Axolotls to persist in areas players come and go from frequenlty

What actually happened was...:
After all players left the area the axolotl was in it would despawn, this happens even without nametags, if one player was nearby it would persist but after all players had left it would despawn

Steps to Reproduce:
1. Place axolotl in player populated area
2. have all players leave the area 
3. axolotls with or without name tags should despawn even if players come and go from the area frequently