Leaf issues with Habaneros and Scotch Bonnets

I have had leaf spot, yellowing, and leaf drop on several species recently.  Have not been letting them get over-watered, but as the weather warmed up, the older leaves started to develop these brown spots, browning on the leaf tip, and yellowing, and eventually they fall off.  Consequently, new healthy growth starts from the apex (armpit) at each node.  I m wondering if this is just normal?
 
I transplanted into fresh potting soil (Miracle Grow), but refrain from adding additional nutrients, but I did apply daconil for fungus once.  did not seem to be detrimental.  We've had a lot of rain in the past two days, but I put everything back in the garage to avoid drowning them.  Hoping things will acclimate to the larger containers, and we'll get back outside just n time for the bugs to attack.
 
Any advice or observations are certainly welcomed.
Thanks!

Geez I hate to say it but those look diseased to me.. I hope that's not the case though. I am a grower by profession now but I'm also not that savvy with identifying deficiencies or disease. I hope it works out for you buddy. It probably isn't related but that soil looks a little sub standard.. What do you have them in?

Too much moisture in the soil would be my guess.

Pic are right after a frog strangler rain day, so yes, wet.  But this started beforehand with drier conditions.  I am using Miracle Grow potting soil alone, with some additional perlite and vermiculite.  I have had some in older soil, but am rotating that out.  With the Scotch Bonnets, some of the plants may be a bit runty, as I grew them from see refrigerated at a grocer.  I have more seedlings ready to plant, and may just discard the older soil, although I had no such problems last year.  Have one SB that is doing great, in new soil, which lead me to that theory.  I pulled everything else in or put it in the frost  box to dry out and survive the next rains coming Sunday.  Sunbathe during the day.  I segregated the funky ones from the rest of the family.
 
THX

I think you are correct in your conclusion regarding the soil. There is likely some funky bacteria in it. If this is the case, it may be too late for the plants pictured.
 
You could let the soil dry out, and do about one or two waterings with a mix of about 1 part hydrogen peroxide with 4 parts water.

I'd say Potassium deficiency
 
Reasons can be:

• Soil high in organic matter
• High magnesium or calcium
• Not humid enough
• Low PH and high salinity
• Low temperature

Do any of these tick any boxes?

Soil was right out of the bag (Miracle grow).  Prior soil may be an issue.  Have treated with fungicide, and isolated, and only one was beyond saving.  The others have begun to come back, with drying out and transplanting.  Hoping for continued success.