Hi,
Same issue.
I confirm that come from the bearing bed tensioning.
FIXED:
• No Need to change it.
→ I used a PTFE lubricant Spray (From WD-40)
Just gently spray on each bearing’s sides.
Maybe WD-40 itself will work.
One more word:
I used this PTFE lubricant everywhere, since its doing the same job as grease, but without caching all the dust, wich avoid accumalting it other the time.
Another Dry lubricant that is perfect: Grafite poweder. Same effect, no dust issue.
I have the same issue: Clicking sound in random y-position on one of my two A1 printers (the newest one). I opened a ticket on it in April, and they sent me a new y-motor that I replaced (a one-hour operation!). The clicking has started again now after maybe 10 more print hours - and now I found this thread.
I’ll reopen my service ticket and request them to send a new tensioner.
IMHO lubrication will only mask the problem (which I assume is inside the bearings), and the printer was new this spring. So I want a solid solution.
Same issue. Gonna try wd 40 on the bearing 
Hi! I ran into the same problem today. Did replacing the Y-axis belt tensioner bearing help? Or could it be something else?