CFB Dynasty Depth Chart Bug

IRL, the 3-4 does not field any DEs, just 3 DTs. To compensate for the lack of edge rushers, you frequently try to generate pressure by bringing a backer or safety (or two) on  a blitz from an unexpected direction.

That's not to say you don't need DEs on your roster. The Nickle formations will will use your rush DEs (which is a separate depth chart position than your regular edges, look towards the bottom of the list of positions in your depth chart). That's where your very best pass rushing DEs should go in the depth chart. That way they're on the field any time you call Nickle.

But that brings up a great point. If you put your OLBs into your regular EDGE depth chart positions to fix the regular 3-4 formations, you create another problem.  Those same edge positions are used in GOAL LINE formations, and you definitely want your EDGES in there (preferably your best run stopping EDGES), so you'll probably want to use formation subs to be sure those EDGES are on the field in goal line formations (and not your OLB you put at EDGE in the depth chart)..

If EA hadn't borked the regular 3-4 formations none of this would be necessary, but it is what it is.

I do recommend you take a look at Mill's spreadsheet (on the 3-4 tab). Which depth chart position is on the field at every position for every formation is very clearly laid out there. https://docs.google.com/spreadsheets/d/1w0Fvvs2fZTLLHUOmvFOxvTpTgPw0mgCkWktGFSUGSZ8/

Once you know exactly which positions are on the field by default for all of the different formations, you can then tailor your depth chart (first) and formation subs (second, to do any formation specific overrides), then you can have exactly who you want on the field at any given time.