From my experience running servers etc, it really shouldn't. Are you sure something else didn't modify the car?
Go into the car folder and look for data.acd check to see the date it was modified.
Also is it just 1 server that you have this problem in Multiplayer or is it on multiple servers? Sometimes a server admin may have modified their car and it translates to server or they failed to update.
If it helps I see my ACD not modified since 5/19/2017 and I think that was due to an update.
On the flipside to fix it you can try removing the data.acd file and then reverify via Steam. BUT, if you have mods installed that modified sounds and other aspect of the cars there's a good chance the verify operation may lay down the default files in place as they will more than likely be seen as not matching the source hash.