Again, they’re not stuck, neither indefinitely nor definitely. The return was on hold to give NASA time to study the equipment before it was jettisoned to burn up in atmosphere. They still have resources (power, water, food, air, etc.) in reserve to last a while longer before they have to leave. (And I’m pretty sure that NASA could resupply them anyway.)
I know I’m arguing semantics here and the rest of your post is probably right but if they unexpectedly don’t have a way to get home right now I think that qualifies as stuck. If there’s no set date where that’s scheduled to change yet they are stuck indefinitely.
The part of the spacecraft that has the issue they’re researching is the part that has already done its job (getting to the space station). That part isn’t needed for the flight home, and in fact, gets jettisoned not long after departure from the station. Thats the reason they haven’t left yet. If they leave, the part of the spacecraft with the problem gets thrown away and they can’t learn anything more from it.