1.13 Turtles won't breed

I'm playing Minecraft 1.13 snapshot 18w10d, and I'm trying to breed some turtles. I have them close together, feeding both of them sea grass. I have them on sand (I think they only lay eggs on sand?), but they're not breeding. I see hearts, which means they're in "love mode", and I get XP after a few seconds, and I wait five minutes after every try, but they don't dig, and they're not laying any eggs. I've tried restarting Minecraft. I've tried this with three different turtle pairs, but to no avail. Any advice?

This is a confirmed bug in the Minecraft bug tracker.

https://bugs.mojang.com/browse/MC-126798