We already know that in some cases there are issues with geometrical compatibility, due to short charging cables and various charging inlet locations.
However, this is not the only thing that was noticed. According to Bjørn Nyland's recent video, there is also a problem that the plug is not securely locked while charging a non-Tesla EV at a Supercharger.
He demonstrated, using a Kia EV6 as an example, that in the absence of the driver, a third party can simply click a button to stop the charging session and disconnect the car. Probably also start a new session with his/her own EV.
It is not a critical problem, because such things are not expected to happen often, but it hints at a process that is not entirely refined yet.
As we understand, only the customer (or the station service) should be able to physically disconnect a car/interrupt the charging session. Now it can be done even by kids for fun, while the driver is in a restroom or shop.
Bjørn Nyland notes that the issue does not concern Tesla cars charging at Superchargers, as the plug is locked.
Only time will tell whether things remain like that or if there will be a solution (software or hardware) for non-Tesla EVs. For now, it's a little thing that comes on top of the geometrical compatibility and often lack of support for vehicles with trailer/larger vehicles.
Because the opening of Superchargers in Europe is in a pilot phase, Tesla has some time to collect experience and develop an ultimate solution, potentially next-generation stations with several upgrades.