Clicking the game-timeline while the path is being previewed makes ReplayMod attempt doing both simultaneously.
This results in a succession of "joining world" screens, interrupted by flashes of the loaded world.

An example can be seen here:
https://cdn.discordapp.com/attachments/709108200632483900/948741869599358976/2022-03-03_01-41-01.mp4
(Discord conversation: https://discord.com/channels/708304818829262910/709108200632483900/948741871184797696)

I have not specifically tested all playback and time-skip combinations yet.

In general the expected behaviour would be, that all playback is paused automatically, when potentially conflicting actions are triggered.