Bug cover of night [can't reproduce]

[Shardeus]

So the targeting issue is the same , but if you mind control an opponents creature while they have it out, you can no longer use elementalis' ability for the rest of the match

[AnAdolt]

I tried reproducing this in v1.26(v1.26-9) and I'm not able to reproduce this. Maybe your Elementalis was just at full health. Currently, with healing effects in SE, you cannot use them if the target is already at full health.