Not sure, but this seems like a but. I can fallback when riding, and when wolf comes to me, I'm already mounted.

This log is when mounted.

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Irdrinil, an elder monk is covered with bleeding wounds.

civilized <77%hp 100%m 100%mv 9484tnl (1.21%) 11 AM>
You retreat from the heart of combat and fall back to a safer position!
Irdrinil, an elder monk is covered with bleeding wounds.

civilized <77%hp 100%m 100%mv 9484tnl (1.21%) 11 AM>

A vicious warg's chomp devastates Irdrinil, an elder monk!
Irdrinil, an elder monk's punch mauls a vicious warg.
Irdrinil, an elder monk's punch mauls a vicious warg.
Your stab EVISCERATES Irdrinil, an elder monk!
Irdrinil, an elder monk is covered with bleeding wounds.

civilized <77%hp 100%m 100%mv 9484tnl (1.21%) 11 AM>
flee
flee
PANIC! You couldn't escape!
Irdrinil, an elder monk is covered with bleeding wounds.

civilized <77%hp 100%m 100%mv 9484tnl (1.21%) 11 AM>
Hallway Through the Monk's Personal Chambers


You flee from combat!

civilized <77%hp 100%m 100%mv 9484tnl (1.21%) 11 AM>

A vicious warg has arrived.

civilized <77%hp 100%m 100%mv 9484tnl (1.21%) 11 AM>
mount
You are already mounted.

If you are mounted, you can no longer fallback behind your mount.

You can still fallback behind your mount when unmounted.

And you can still fallback behind OTHER people while mounted.