Breeding tamed ex-Wandering Trader llama's won't result in baby llama's

In Minecraft v1.14, I captured some loose llama's from the wandering trader, tamed them, equipped them with chests and carpets.

Breeding these llama's in 1.14 was no problem.

Now in 1.14.1, when I feed the llama's hay bales, they enter love mode and seek each other out. XP orbs appear but no baby llama's.
Tried this with multiple llama pairs and over multiple Minecraft days.

MC-151702 also described this issue but contained insufficient information to be useful.