Why the match may not be what the file asked for (an unusable layer height or a nozzle size with no U1 profile), as sentences.
The pick came from the source file's own tier name (e.g. "Extra Fine"), not nearest layer height.
"auto-tier-name"/"auto-exact" are confident; "auto-nearest" is the closest available layer height; "default-fallback" means no match at all, so the profile is just the catalog default.
Keep the source file's own layer height (auto-matched to a tier that isn't an exact layer height match).