[Answer from an external angle, being Germany]

Your situation sounds very similar to a peculiarity of the German language which means that we've solved it for a very very long time.

In German we have "du" and "sie" both as a translation of "you". The first being colloquial, being used among children, teenagers and friends or colleagues (and increasingly chefs as well) but between adults "sie", the more formal address is the default. It's what students address their teacher by, it's how two random adults (especially in formal settings) address each other until one "offers the 'du'" (if there is a hierarchy the superior has to be offering it), thereby deformalizing your relation (to some degree) intentionally.

It's not as strict anymore as I made it sound but I think it still very very neatly fits to your case: you have a valid claim to the default formal title of doctor (or as Bryan Krause points out maybe only PhD) which you may choose to waive in social interactions (though your behavior can, as it seems you wanted to imply a company- or station-wide waiver), but never, ever, would an official buisness email (unless it's restricted to a close circle that the sender knows you're all "per du" with) use the informal "you", especially not when some other people (of the same organization) are referred to formally.

Tl:dr: from a German perspective it's a noticeble fauxpass of the email writer to not at least include your PhD. Depending on what age and/or social group you'd ask demanding a correction may still be seen as petty (though some older folks would also consider it adequate). Simply asking for it to be respected in the future is very valid though.

Especially when there is (occasional/frequent even?) discussion/uncertainty about your (implied lack of) formal training, leaving it out in an organization-wide (plus more) invite to a presentation you provide (while others have their title included) is completely inacceptable and would be seen as a grossly negligent or an intentional transgression. In larger organisations contacting HR about it would be at the upper end of "adequate" response (and would be perceived petty by some) but would still be seen as reasonable by many.

Small note: Because we have this delineation of formal and informal addressation, titles aren't as important to a lot of people (because leaving out a doctor while using "sie" still definitely reads respectfully) but it still tracks, and when some in an email invitation had theirs included, omitting them for others (unless they're completely unrelated titles) would be a mistake at best.

[Answer from an external angle, being Germany]

Your situation sounds very similar to a peculiarity of the German language which means that we've solved it for a very very long time.

In German we have "du" and "sie" both as a translation of "you". The first being colloquial, being used among children, teenagers and friends or colleagues (and increasingly managers & bosses as well) but between adults "sie", the more formal address is the default. It's what students address their teacher by, it's how two random adults (especially in formal settings) address each other until one "offers the 'du'" (if there is a hierarchy the superior has to be offering it), thereby deformalizing your relation (to some degree) intentionally.

It's not as strict anymore as I made it sound but I think it still very very neatly fits to your case: you have a valid claim to the default formal title of doctor (or as Bryan Krause points out maybe only PhD) which you may choose to waive in social interactions (though your behavior can, as it seems you wanted to imply a company- or station-wide waiver), but never, ever, would an official buisness email (unless it's restricted to a close circle that the sender knows you're all "per du" with) use the informal "you", especially not when some other people (of the same organization) are referred to formally.

Tl:dr: from a German perspective it's a noticeble fauxpass of the email writer to not at least include your PhD. Depending on what age and/or social group you'd ask demanding a correction may still be seen as petty (though some older folks would also consider it adequate). Simply asking for it to be respected in the future is very valid though.

Especially when there is (occasional/frequent even?) discussion/uncertainty about your (implied lack of) formal training, leaving it out in an organization-wide (plus more) invite to a presentation you provide (while others have their title included) is completely inacceptable and would be seen as a grossly negligent or an intentional transgression. In larger organisations contacting HR about it would be at the upper end of "adequate" response (and would be perceived petty by some) but would still be seen as reasonable by many.

Small note: Because we have this delineation of formal and informal addressation, titles aren't as important to a lot of people (because leaving out a doctor while using "sie" still definitely reads respectfully) but it still tracks, and when some in an email invitation had theirs included, omitting them for others (unless they're completely unrelated titles) would be a mistake at best.