MB-38978 it's been identified that there is a lock which can cause kv-engine to not process any operations for a long enough period to cause the 2.5s timeout to be triggered here. This should be release noted as discussed in MB-45125.
MB-38978: Under certain circumstances, such as running a cbcollect_info, requests may take longer than normal. Depending on the system workload and size, this may be even a few seconds, which can trigger the default timeout value from SDKs. It is recommended to avoid gathering these stats or cbcollect_info during higher workload.
Or something like that…