CalMg? maybe. That's what happens to me when I used RO water. Also if you don't allow your pots to dry out well and then continue to water them they get start yellowing, tips get burnt, and etc..I think it looks like you may be overwatering, drowning your roots and causing multiple deficiencies. this happens to me sometimes when repot, if you don't let them dry out they will lock up on u.
Everytime I have had spots, and they usually start yellow end up reddish and then die. CalMg fixed it, Iron is usually in there too (the CalMg). {
Good luck man