Need Help Urgently – PSU Keeps Tripping

http://imgur.com/gallery/ZdBXatQ

Here's my rig setup shown above:

4 x 3060 Tis on the top row connected to PSU 1

4 x 3060 Tis on the bottom row connected to PSU 2

1 x 3070 Ti, 1 x RX570 and 1 x RX470 mounted on the case connected to PSU 3

The 3060 Tis are all at 171w each, The 3070 Ti is at 255w, The RX cards are at 140w each, The motherboard is connected to PSU 3

PSU 1: Corsair CX850m – 850w Bronze, PSU 2: Super Flower Leadex – 850w Gold, PSU 3: Antec TP-750C – 750w Gold

So I initially noticed the top 4 would switch off momemtarily (causing them to disconnect from the system and not show up again unless I reboot) after a while no matter what OC I applied (rest of the rig still powered on and mining fine), I realised PSU 1 is the problem

PSU 1 connected to the 4 cards would be pushing 684w, which is roughly 80% of 850w, given this I thought PSU 1 must be packing up to trip under that load and I need to replace it

To alleviate this while waiting for the new PSU I then removed 1 card from PSU 1, now only pushing 513w, and connected it to PSU 3. I removed a single RX570 from PSU 3 when I moved the 3060 Ti to it

Everything then ran smoothly for a day, so I thought problem solved it was just a faulty/weak PSU

But now the same thing is happened to PSU 2 (which powered the bottom 4 x 3060 Ti), it tripped and the bottom 4 switched off momentarily again while the other PSUs are fine and the rest of the rig is mining normal (including PSU 1 that now has a reduced load)

I could understand PSU 1 being faulty since its bronze and 4 years old, but PSU 2 is brand new and gold rated so I don't think it's at fault

Can anyone please advise why PSU 2 is now tripping even though its pushing 684w which is 80% load

The 3 PSUs are connected together via one of those splitter things

I've tried changing the power strip – didn't help, tried changing the PSU power cord didn't help

I'm stumped, any ideas what could cause these PSUs to trip momentarily at 80% load?

If you guys need any more info/pics please let me know I'll try and reply ASAP

Any help would be appreciated

Thanks