Hello,
I had a 65s that I sold quite quickly because it had a fault the Galileo satellites (multi-band or not) were still flashing, it really took several hours of operation for them to be taken into account, then I bought a 66sr but had exactly the same problem, what was my disappointment.
Today Garmin released a new firmware 4.90 for the 66sr (for the 65s too) which completely corrects this defect that I had reported to Garmin-France (they don't care) and to Garmin USA which gave me answers but not convincing.
Now the multiband satellites are all taken into account and the fix is done quickly. Problem solved therefore.