When a device is deleted in Spectrum, the device is not retired in CAPM
PTF_10.1.103 (for Spectrum 10.1.1) must be applied to resolve this issue. An issue must be opened with the Spectrum team to get this patch, and it should be applied per the release notes. Also, within CAPM, you must go to the data source list, edit the Data Aggregator data source and make sure "Discover devices from other data sources" is checked as well
See the CAPM compatability matrix: Compatibility Matrix as there are a few different PTF patches that may be applicable depending on the version of Spectrum oyu are running