Sometimes double clicking on apple watch does not work

Occasionally when I am in a store ready to use Apple Pay via my apple watch and I double click on the side button to bring up a credit card, the credit card does not come up but the there is a flurry of displaying various apps (like it wants to show the dock). I end up using my iPhone to complete the transaction. When I get home, I try it again, and the credit card appears just as it should. Might it be certain terminals that cause this? This has happened several times at a Publix store, and once or twice at Aldi, but not always at either store. This has been a problem since the last update I believe, but may be coincidental. If I reboot the watch, it behaves OK for a week or so at any store.