In creating a new watch only wallet in Blue wallet, I import the default public key from Sparrow to Blue Wallet. The default in Sparrow is xpub, so that's what I import.
Blue Wallet picks the wrong derivation path.
Blue wallet picks m/44’/0’/0’, when in Sparrow the derivation path was m/84'/0'/0'. This is all with defaults in Sparrow.
This leads to Blue Wallet not finding any of the transactions, because the receive addresses are different. Also it looks like in Blue Wallet, it's not possible to change the derivation path.
However, in Sparrow when you switch to zpub (by clicking the button to the right of the xpub/zpub field), and import that into Blue Wallet, everything works well.
I've run into this before, and it caused me a major headache. Asking AI tells me that zpub is more modern and efficient, and results in lower fees.
Is that true? I have a hard time believing that Sparrow (which is pretty much the flagship bitcoin wallet software) would do something that's not the latest and greatest. Also this particular AI says that the xpub addresses all start with 1, which is definitely not true, mine start with bc1.