Capabilities being overwritten by other groups?

I have two groups I’m adding to a user.

patients – capabilities: read & patient_read

veterans – capabilities: vet_read

My user is a part of two groups now, patients and veterans, with 3 capabilities: read, patient_read, and vet_read

When I add the second group (veterans) to the user, patient_read gets overwritten, or lost, or something.

if (current_user_can('patient_read')) { // do stuff }
elseif ((current_user_can('doctor_read')) { // do stuff }

The first condition will evaluate to false, meaning the patient_read isn’t being respected. When i remove the veterans group, all works as planned and the condition will be true.

Why would the veterans vet_read be messing with a capability from another group?

Thanks for any guidance.

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