When trying to add a custom web part to the page, looking up existing web parts fails in cases, where the registered web part id either uses a different case or is wrapped it curly braces. Code comparing the IDs at https://github.com/pnp/office365-cli/blob/20495a1c0f378a28e584ef434f55de3cece64b63/src/o365/spo/commands/page/page-clientsidewebpart-add.ts#L242 should be extended to accommodate for these possibilities.