Amend owner out of plan then back in--discrimination?

A few years ago, sponsor amended plan to exclude by name two partners (there are several other partners in the plan).

Now they want to remove that exclusion.

Are there any discrimination issues given the fact that the amendment only affects HCEs?

I wouldn't think so because the HCEs aren't getting special treatment per se.  They've otherwise satisfied the age/service conditions.  It's not like they are being let in early.

I just want to make sure I'm not overlooking anything.

I think you're fine - "It's not discriminatory to stop discriminating."

Is this a DC or DB/CB plan? If DB, be careful this is not (or doesn't start) a pattern of amendments of such nature and frequency that in practice creates what IRS might challenge as a discretionary plan and/or potential non-compliant CODA.

DC plan.