I have a Ender 3 using octoprint with a BL Touch. I have use this set up for years without issue. Recently I’ve been getting a lot of error messages about the BL touch. When a print starts it goes through the homing, but the probe does not extend before checking the middle of the bed. So far my quickfix has been to turn off the printer wait a few minutes and turn it back on. Then on the ender 3 menu I go to configuration, BL touch, reset. After I reset it I go and do a self test this seems to fix the problem. When I go to restart the print it starts without issue. I am wonder if this is an indication that might be BL touch probe needs to be replaced. The only software change that has occurred recently is upgrading octoprint. After upgrading octoprint I didn’t seem to have any issues initially.
To me this does sound like mechanical wear in the probe, but I’ve never used one, and others may have more educated opinions.
Could just be that the probe is dirty, Or bent. You can take it out from the top and have a look they sell spare probes on 3dpc’s main site.