europa - pleasure to help!
I don’t know if you noticed, but the manual says that when performing the stand-by mode on/off procedure, if the hot water button flashes it’s enabled. Otherwise disabled. This correlates with your remark in the opening post:
europa The first time it happened, it was the bottom (HW) LED that did this. Ever since, however, it has only been the top (1) LED.
So looks like the first time it happened, magically the machine activating its own standby mode feature. And what you’ve been seeing since is the machine just going into stand by mode (top button flashing).
Did anything happened on that eventful day? Did you notice the machine settings been completely reset my any chance? Did the machine perform the start up routine? Was that when you changed the cable to a shorter one?