I reported this sometime ago in the Convoy's BLF thread here.
The solution I resorted with was posted there. Summarizing, I used some fine tip diamond files to remove the solder mask from the upper ground ring track. This is rather important for these drivers to operate correctly:

It can also be convenient to remove the temperature protection in these and related drivers; it involves removing the onboard NTC thermistor and is explained here: Convoy 17/22 mm SST40 Driver temperature protection removal.