I created a dual layout to compare two folder structures sorted by month 01 - 12. When I tried to link 01-01, 02-02, etc. I stumbled across an apparent maximum of eight linked tabs. I am guessing that the limit has something to do with associated colours? Personally I wouldn't mind if the colours were cyclically repeated so that folder 9 would be branded with the same colour as folder 1.
8 is the limit currently.
If the two folders have the same sub-folders (month names or similar) on both sides, maybe Navigation Lock would work better? That allows you to go in and out of folders on both sides at once when you move around on either side.
Yes, that's certainly an option. Not as eye catching as the colour coding. 
You could color the folders via labels.
Touché 
I use linked tabs all the time and the limit of 8 is a nuisance. Every new version I look for this feature being updated. Is it not possible that you could up this limit?
We'll increase the limit to 16 in the next update.
Can't say fairer than that! Many thanks
@Jon Did this actually get updated?
Yes, in 12.22.3.
Correct. The colors cycle around a second time, so pair 9 use color 1.
Thanks for the clarification @Leo