Bed Flexing Need Help!

Flexing Printbed Please Help!!!
Noob here, I've only been printing for a few months. Decided on a DIY kit (He3d H500) to learn exactly how the whole thing works and it has presented me with so many delightful problems for me to overcome and thus far it's been relatively easy and a great learning experience... That was up until 3 days ago when it stated making a horrid clicking noise always at the same spots on the y axis. Took off the belt at it still made the clicks when I moved the bed by hand. So I realigned the two bars that the rollers roll on and the noise stopped... But then when I went to level the bed and the front left and back right leveling screws tightened all the way and the other two corners loosened till the nuts fell off.
I've since taken apart, realigned, squared, and leveled every structural component and my printer is prolly the best it's ever been aligned... But the bed leveling problem persists. It does it with both the cast aluminum plate and the warped glass plate it came with. Google has failed me so now I'm here hoping someone has had a similar experience knows what's wrong, how to fix it and who could lend me their wisdom.
Any suggestion might help. Please and thank you, I'm at a loss.

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