Help with Tekcel 2400x1200 cnc router bad vibration in 1 direction

Hi all i have an old Tomotek Tekcel T Series cnc router and every now and then i get this bad chatter issue.

Its not all the time although could relate to weather conditions i haven't taken a great deal of notice.

But when cutting, or even jogging above the table, in 1 direction it sometimes makes this extremely bad vibration resulting in chatter and tooth marks in pieces.

Under the machine the 2x 25mm leadscrews vibrate a lot when this happens.

I'm not sure if its bearings on the linear rails or if its more an issue with the ballscrews.

Any advice on where to start would be great if anyone might have some knowledge or logical explanation as to what they think might cause this issue.

Please see the attached video

https://youtu.be/QbNRdMCoTEo

Thanks for your time

Did you solve it?
That looks almost like one of the lead screws might have a tiny bend in it- hence it cannot handle a rapid rotation at a certain overhang either side of the ballnut.

My only sugggestion is perhaps try lowering the acceleration, and also speed, in the Tekmov settings - I'm guessing that's the X axis? See if that makes a difference - ie a more gentle speeding up.

if you run a job at the other end of the bed, does it run normally - ie is the only issue that particular spot?