Exactly what the title says. Single bottles work fine, but if you try to place from a stack it doesn't work.

We found this bug also.. apparently shift clicking the stack to transfer the bottle also functions as a work around.

Edit: The bug is only present when the "No potion shift" client side feature is enabled. Simply disable it and it will work like vanilla. I'm not entirely sure what this feature is about. According to the code for the feature it simply cancels the potion shift event.