Hello Thomas,
Theoretically, it's possible, but that would require the timing to be significantly misaligned. It's possible that a cable or connector was damaged during the work, or that it already had a loose connection that is now causing problems. Alternatively, something else could be broken that has nothing to do with the timing belt replacement.
When the indicator light illuminates, it means that the vehicle has at least one error code stored in the engine control unit, and something is not functioning as it should.
Guessing games about which error is present are pointless; use a tool like VCDS to read the error codes, and then you'll know.
In addition, it can also be used to check the accuracy of the timing belt setting (offset between camshaft and crankshaft).
Best regards, Rainer.