Why is my Fidelity 401k Value so far off?

You say "when I entered my Fidelity 401k into Quicken Premier it showed a market value…"

Are you telling us that this is your first time creating the Fidelity 401(k) Account in Quicken? If it is, then how did you populate it i.e., get transactions into the Account? Manual entries, or an initial download from Fidelity?

Are the (presumably existing) Roth IRA and Rollover IRA Accounts properly stated, populated by correct transactions and security values?

Each Account in your Quicken file should be directly connected to an existing "real world" account and, in the case of downloading, only "fed" information from that real world account, but from the sounds of it all the information in all the Fidelity real world Accounts are being fed into this new 401(k) Account, something that doesn't even sound possible.

If this is indeed a new Quicken Account and all other Quicken Fidelity Accounts are accurate my instinct is to delete that new Quicken Fidelity Account and try again.

The process of establishing Accounts in Quicken should be pretty straightforward. You create a new Account in the file, establishing what kind of Account it is, e.g., checking, credit card, investment, etc., tell Quicken the real world account is at Fidelity, provide Quicken with the needed login information, and then when Quicken finds that real world Fidelity account, connecting it to the appropriate Quicken Account.

I assume that's the process you've been using, so your situation is a puzzler.