Neighbour spelling in SNOMED CA 2021-09-30 shows the preferred version as being like an American spelling (neighbor)

In Alberta we also have somewhat of a hybrid and transition status in some places. By default we utilize International standards, such as the American style spelling, to produce as much consistency as possible since the International release is the core for the majority of the content.
I personally have found that the UK "ae" in terms such as Pediatric/Paediatric cause more problems than the "our" in terms such as labor/labour due to the smart search functionality. The inconsistency is frustrating, I agree, but can also understand the difficulty of the decision for Infoway Canada as the upkeep on these terms would be very time consuming.

For sure the SCTID should be stored in the EHR. That goes without saying.

Ideally, the term that was displayed in the user interface when the record was made should also be stored.

You're absolutely right. The code is the canonical representation of the concept and as such should be the key for every Information System developed. However, we're in a transition world, where many Information Systems out there don't know about SNOMED CT, and they are allowing 2 characters to specify the sex, or next of kin. So, putting the SNOMED CT ID is a no go for these systems.

The label though, is always available, and so our team is helping bridge that transition, and provide mapping tables between "house codes" an SNOMED CT codes; while still providing the label itself.

Why are you storing a text phrase in the EHR instead of the code? The UI can interpret the code as per the end user's language settings. That was how it was sold at the meeting at which CHI decided to use US English.

I believe it depends on how the language preferences have been configured within a specific implementation.

Many organizations will chose to allow searching over all available synonyms (for greater flexibility) but then restrict display and data entry to one specific language.

So for example, you could search for the procedure "induction of labour" which would return results such as "induction of labor" which is the term that would would get stored in your EHR because you have selected Canadian English as your preferred reference set. (Click the link below to see a screen shot.)

https://drive.google.com/file/d/1KDsbIpXExgThMRCBHsOiN7FohR-PYJsC/view?usp=sharing

This may not be ideal for some people who want to see the Canadian spelling in their EHR, but as phumphies has said, both of these terms point to SCTID 236958009 which has a universal meaning.

Even if the language preferences are set at the user level, I don't believe its really feasible to display some terms using US English and some using UK English. It's more or less an all or nothing thing.

I would run a script to replace all the descriptions that can be matched to terms in the UK set with the UK descriptions, myself.