Am reporting this against libsigrok which contains device drivers and input modules which assign channel names upon probe/scan or file read, and which contains common support code to rename channels.
Applications may need adjustment to not DIY but instead to use common library code to rename channels.
User sse reported via IRC that pulseview lets users assign empty names to channels, which is unexpected to me as a developer. That's probably why it went unnoticed in the past. Pulseview reload then is reported to confuse channels, which may be due to channel names being (used in) .conf file setting lookups (just a theory).
I strongly believe that sigrok channels need to have names, and that names should be non-empty. Device creation and import opening can enforce that, as can the common channel rename support code. Users should consider this acceptable, as it is useful for used channels, and unused channels can get disabled when desired.