Entities on clients are rendered burning even despite a modded server not flagging them as such. This leads to entites visually appearing to burn despite a server not damaging them.

I've discovered the reason for it in the MCP while hunting it down for a mod I'm making:

The method on the Entity base class, that checks if the Entity is burning, is currently saying:

"True if this entity is not immune to fire AND ( its fire level is bigger than 0 OR ( this is client mode AND the server says it's on fire ) )"

This leads to the client always rendering flames when it's own calculation of an entity's fire level (which is apparently not always skipped in client mode) results in any positive value, as the second part of the expression is never evaluated.

What it should correctly say is:

"True, if this is client mode AND the server says it's on fire OR this entity is not fire immune AND it's fire level is larger than 0"