[Vanilla Bug] Objects clip through large unit graphics

[Crimsonum]

First Check

• [X] I added a very descriptive title to this issue.
• [X] I used the GitHub search to find a similar issue and didn't find it.
• [X] I have attached as much information as possible (screenshots, debug and exception logs, etc).

Description

Units can only ever occupy a single cell. If there are multiple units standing on adjacent cells, the units at the back are obscured by the units at the front. For the most part this is as it should be, however units with large graphics that extend outside the cell's limits will suffer from objects seemingly clipping through.

In other words, units with large graphics may not be correctly layered relative to other nearby objects.

See a similar issue #888.

Required Code (optional)

No response

Steps To Reproduce

The GDI Dropship is probably the best unit to reproduce the bug with. Simply play any mission with dropships in it and watch what happens as the Dropship unloads its passengers.

Expected Behaviour

Because of its large frame and height, the dropship should obscure its passengers as they exit.

Actual Behaviour

The passengers clip through the dropship.

Additional Context

Demonstrating the bug in TS Rubicon, which uses a much larger model of the Dropship for increased effect.

Also note how the dropship correctly covers the unloaded units the moment it takes off.