NAT-PMP: Unable to allocate port for mapping (Mikrotik RouterOS)

[dragon2611]

What is the issue?

Enabling nat-PMP support on routerOS caused the router log to be full of the following message "unable to allocate port for mapping *:0 -> 10.52.0.12:41641, timeout 7200s"

I'm not sure if this is a bug with tailscale's implementation of nat-pmp or a problem mikrotik side, enabling uPNP instead does work (But you do also have to manually create a firewall rule to allow udp/41641 as EST/Related isn't enough allow direct connections it seems).

Upgraded the routerOS side to 7.14.1 which I believe is the latest stable.

Steps to reproduce

Enable Nat-PMP on a Mikrotik router (the trial version of a CHR should work if you need one for testing)

Are there any recent changes that introduced the issue?

No response

OS

No response

OS version

Nixos 23.11

Tailscale version

1.58.2

Other software

No response

Bug report

No response