Registered key not recognised

[realdmitchell]

I bought 2 solokeys (solo1) may be 2 or 3 years ago. Both are at

solo1 key update
Wrote temporary copy of firmware-4.1.5.json to /tmp/tmpq8hpndbc.json
sha256sums coincide: f36bb365bfddf75004f28af392ae1439192ca0ed821ef496084a75a00d05087a
using signature version <=2.5.3
erasing firmware...
updated firmware 100%             
time: 9.27 s
bootloader is verifying signature...
...pass!

Congratulations, your key was updated to the latest firmware version: 4.1.5

Till June I did not update the key and it was at some ancient version - cant remember - something old - from the manufacturing may be )

Since the update, whenever I register both keys (in the consecutively within 2 minutes of each other) they are recognised individually. Note that I physically remove and plug the next key so there can be no mistake that I forgot the key change. A few days later when I use a certain key I get the error.

Then I use the other key. Login. Then try to add the SO-CALLED -unregistered key. The website (like Github or Google) will say - this key is already registered.

Now logout and try the failed key. It works fine.

For the accounts where I did NOT consecutively within 2 minutes of each other register keys - like lets say I register key 1 on Monday; and key2 on Tuesday. Then these accounts show no problems.

Could you please help? This is also worriesome.