Problem with Forest Fire Monti Digi frag

[vaporlockv2]

So I noticed yesterday my forest fire wasn't happy. As my snails frequent the frag rack it's on didn't think anything of it. Now the tips are missing flesh and very little polyp extension. Have several frags from the main colony all are doing well except this one. Had it for a little over a month and been doing great and growing very fast. Lighting hasn't changed, flow hasn't changed.
Parameters are
Salinity 1.025
Alk - 8
Mag -1350
Calcium -480
Phosphates register zip on API test kit
Nitrates - 5ppm
Parameters are always consistent. Alk drops to seven daily before dosing of course. Any ideas?

[vaporlockv2]

Oh and have check for any sort of pest and nothing. Also tank is sps dominated with pretty fickle acros and NOTHING is affected except for the one frag

[Will Haider]

Could it be that the alk spike was larger than experienced before malfunction of a doser or just a heavy hand?

[vaporlockv2]

I'm not sure. Seems to be doing better today. So could just be a fluke?