The command spo app add allow to upload .sppkg file into an Apps Catalog.
This command returns some information once done.
Launch the command m365 spo app add ...
Return the GUID of the uploaded app only
The command return Unique Id: [UID]
Note: replace [GUID] with the GUID of the app
For the case of the custom scripts to deploy app, the current solution is to replace UniqueId: but in the case of the GitHub Action, it is not possible and that does not work anymore
Example to remove UniqueId in bash:
appId=$(m365 spo app add --filePath ./my-app.sppkg --scope sitecollection --appCatalogUrl $siteUrl)
appId="${appId/UniqueId: /}"


Thanks you for letting us know @Laul0 apologies for the trouble we will take a look ASAP.
Has this changed recently?
Approximately 1 week ago
It seems like we've unintentionally changed the command output during a refactoring last November. We should revert our change to prevent breaking changes in minor versions and reconsider the current implementation for v4 later this year.
Hey @Laul0, we've just released a new preview version with this bug fixed. Current version will be released at the end of the month. Once again, thank you for reporting the issue and sorry for the trouble.