A long time issue with many devices. The strap is still wet and trying to connect to the watch. I don't know why it seems to always read in the mid 200's. You have to be out of range of the strap and it will stop trying to connect.
The strap should generally shut down within 2 minutes of you putting it down. If you keep picking it up and moving it and trying to "solve" the problem, it will stay awake.
The strap is telling you it's going dead. Mine did similar things, but it was when I wore it and it just transmit much higher than my normal heart rate. I bought a cheap Decathlon strap and used Garmin sensor with its strap. So it's fine now. Try removing the sensor from strap and if it still transmits, the chip may be faulty.
