You can deploy onto other units

[PunkPun]

In TS I gave the Subterranean APC ability to transport vehicles on bleed
Then moved tick tank into it and double clicked the deploy button

[PunkPun]

I just realised that this bug can also be reproduced in RA with MAD tanks and Transports. Tho it doesn't show the glitchy undeploy from the gif above

[pchote]

The issue here isn't related to transports and isn't specific to TS.

GrantConditionOnDeploy has regressed to allow units to allow these units to deploy when they are off-grid. This can be reproduced with a normal move order and the /terrainoverlay mode to compare vs the standard cell grid.

[tovl]

Currently, DeployForGrantedCondition doesn't check if the deploy location is valid at all.

To fix this, DeployForGrantedCondition should call deploy.CanDeploy() in OnFirstRun.

It turns out this actually has nothing to do with GrantConditionOnDeploy (not surprising considering MAD tanks don't actually use GrantConditionOnDeploy). You can see a similar thing happening when you double click a normal move order while entering the transport: the unit will instantly teleport to an adjacent cell. The fault is with MoveIntoWorld, which should not be interruptible.