Prometheus High Memory and CPU Usage in PMM
100% RAM -- You are probably swapping, which is terrible for performance.  Lower innodb_buffer_pool_size a little to avoid swapping.

200% CPU -- Poor indexes and/or poor formulation of queries.  Please provide some of the queries and SHOW CREATE TABLE; there may be a quick fix.

"out of order" and "different value" -- Either a bug with the collection mechanism or a bug in Percona.