Follower Freezing/Getting Lost in Nightingale City

The Follower AI can be a bit glitchy at the best of times but, since arriving in Nightingale, my assistant's spent more time stuck in place on the map than being anywhere near me unless I stay slow and close.

As soon as I grapple or use my umbrella glider for extra speed, they're lagging way behind and eventually stop moving entirely. The teleport catch up mechanic doesn't seem to be applying and I can often stop and look back with a spyglass or the longbow zoom and see them just standing idle where the motion halted.