LPS bailing, possibly several reasons

[AVVITT]

I've had 4 LPS bail in the last 6 weeks but I'm finding it hard to pinpoint a specific reason.
I appreciate several things going on may prove difficult to find reason but I'm hoping some if the more experienced may be able to give me a few pointers please?!

A timeline of events may be the most useful and bear in mind all coral in question have been in my tank for at least 3 months prior to recent events.

Approximately 6 weeks ago I moved over from dosing Reef Zlements kh buffer, magnesium and calcium to Tropin Marin all for reef.
I also started doing water changes again (the first of which was approx 25%) after 6 months because my tank wasn't looking as crisp as it can (Tropic Marin pro reef salt has always been used since day 1)
During the time of the switch over, I lost a small octospawn which withered and eventually bailed. Didn't think much of it because everything else looked great so thought maybe the change/imbalance of different elements etc.
I did have a cyano issue and my phosphate bottomed out so I fed heavily for a few days (took 3 days for phosphate to get up to 0.03)
I had also started using coral snow which is calcium carbonate mixed with a little mocrobactor7

I have been testing kh, mag, calc and phos every 2-3 days while getting used to the new dosage amounts. I had seen both my calc and mag dropping though kh was stable at 9dkh.
I started dosing TM bio-magnesium alongside AFR because my mag had dropped to 1220 while usually always being around 1350. This also has the same 70 trace elements as AFR

1 week later, a second octospawn also bailed which had me concerned but my own tests and tests my LFS ran all came back ok. My LFS suggested possible iodene but that came back as low rather than high. He did suggest it may have been the heat (we had an unprecedented heatwave where the outside temp got to 40C and the tank did probably climb a couple of degrees higher than normal)
So we concluded possible that the warmer conditions had caused the issue or even possible the phosphate drop out?

I decided on an ICP test to be safe which due to a number of postage issues (Brexit!) My ICP didn't come back until yesterday, the samples of which were only re taken last week and I've attached on here.

So last week (5 weeks after my first bailout) one of my torches bailed which is when I sent my second ICP test after my first failed one!
I had also done a water change (10%) that weekend and once again used coral snow.
3 days ago, I did another 10% WC and once again used coral snow then yesterday I noticed another torch, literally bailed within 24 hours after looking really plump and happy just before.

HELP!

 

[Wasabiroot]

If I had to guess, too many changes and swings. You kind of say it in the first paragraph- six weeks ago it started, six weeks ago you swapped to AFR, nutrients bottomed out, started changing water again, had a temp spike, low magnesium, then high magnesium, etc.

Corals are slow growing and sometimes changes they don't like take a bit to show their effects. Perhaps you're just dealing with collateral from the past.
It's likely not iodine - it is present in salt mix and a deficiency is hard to diagnose as it's used up pretty quickly.