Maybe it has to do with gigabit port autosensing for the used data cable pairs.
Gigabit ports normally autosense which pairs of RJ45 are available and how they are used. This is why for example you don't need cross-over cables with gigabit.
Could it be that the two ports sensing timings, on Tik & Uqiuity, are colliding with each other?
As an anecdote, I had once a faulty cable, and my gigabit port would connect over the cable, but after a long delay and only at 100mbit, as 100mbit only requires 2 pairs, while gig all 4
In other words: have you tried putting a plain/dumb switch in-between?
Hi... I also thinked my problem could be caused by autonegotiation
But I tried many things like set port speed manually.... ecc. I don't solve anything....
Besides, putting a switch in the middle I have the same problem... but if I power off mikrotik and reboot ubiquity it work fine...
In this case autonegotiation is between switch and ubiquity... how mikrotik can change ubiquity working???
Someone known how device understand if in ethernet port there is a connected cable??? I think that could be some electrical problem (impendance)