[EDIT: Somehow didn't notice that the ticket in question specified taking time to display, thought it was always about it not disappearing. Could that ticket perhaps be made to only apply to them not disappearing afterwards?]

Relates to MC-47660, probably the same cause.

When a barrier block is placed, or when an existing barrier is visible when a barrier item is switched to, the barrier particle will not appear instantly, even though it probably should. This is especially visible if there are a lot of barrier blocks present.

This is also likely a parity issue.