Do you think you might've seen squash bees on your plants before?
Squash bees can look similar to honey bees but will behave differently. One noticeable visual difference is that female squash bees have hairy hind legs that collect dry pollen from squash flowers as opposed to the legs of a honey bee which typically collect pollen in a clump near the top of their smoother leg. You can see some squash bees at the beginning of this survey for further reference, but feel free to just take your best guess!