The LED on the front of my MBL is flashing blue

The functions I use were still operating normally, but flashing blue isn’t one of the LED status indications listed in the manual.

I turned it off and on again, in the approved manner, and normal behaviour continues, with steady or flashing green, or steady blue, so this is not a current problem.

Even so, if anybody knows what flashing blue means, do please let me know.

it probably means the light is starting to fail.

I don’t think so. It hasn’t done it again since i rebooted, and has shown no other signs of failure. It displays steady blue, steady green, or flashing green as appropriate according to the manual.