Please see the video at the end of this post for a demonstration of this bug.
Ventari has always been rather clunky, but has been made somewhat playable with the recent changes, especially the reduced cd on Ventari's Will (#6 / moving the tablet).
Combined with the casttime of the actual skills outputting healing on ventari, the low CD of #6 is needed and key to making the heals land.
Instant cast is supposed to further aid with keeping the tablet on a moving target at all times, however it tends to do the exact opposite at times.
As shown in the video, "spamming" #6 (in order to keep it on a moving target) bugs out the tablet and makes it return to the player/owner of the tablet. This is then quickly overriden by the next #6 input, making it look like a short detour. (best showcased at 0:41)
Obviously, having this happen right as the skill outputting healing is done casting is game breaking.
Taking off instant cast is a player side solution to this, sadly this completely defeats the purpose of the now reduced CD of #6, as the effective casttime doubles with the added aoe marker.
With recent changes to Ventari and upcoming changes to scrapper and druid & those to firebrand more in the future, the potential for a more diverse support landscape is coming.
This bug heavily cripples Vindicator support builds running Ventari, a fix without again increasing #6 CD would be heavily appreciated.
https://www.youtube.com/watch?v=qafD0MIpDJ8
Edit: In this second video, the same bug can be observed without changing the position of the mouse cursor. Even though the mouse isn't being moved at all, the tablet still returns to the player upon spamming #6. https://www.youtube.com/watch?v=f9owLg9h5s0