What the title says.
If I have a companion active, summon an assistant (unsummoning the companion as a result), then unsummon said assistant (causing the companion to re-summon), the companion summons with zero ultimate, but cannot use their ult ability even when they get it full again.
I did not do thorough testing, but at the very least, it consistently happens with following conditions:
* The companion had full ultimate before being unsummoned
* Companion's ultimate use is set to manual
* I stay in the same zone