Retreating the summon but the summon’s moveset does not disappear.
Have you already checked if the summoner has the same Skill type as the summon?. You should use a specific skill type for summons, so their skills will could only be used by them. (or him)
1. Create a skill type called "Summon Skill"
2. Create a skill that has the skill type you created "Summon Skill"
3. Assign the skill type "Summon Skill" command to a summon.
4. You should add a skill that belongs to that specific skill type to your summon. "Summon Skill".