It's not within the vanilla game but it's still very much within the mod files. You can add it to almost any tank and light vehicle, using the marker_ext within EBPs.
Shoutout to Eebies for the help figuring out that basically any vehicle can carry troops on top.
I had this happen to me about 6 months ago. For me it was a psu issue that happened on coh2, and rarely in a few other games. Upgrading to a better psu with a less crappy rating fixed it perfectly.