Hi there!
@Michael_Coburn, I know MongoDB is not Percona’s product and of course you have paid support options but I thought it is good all forum users to know that you have experts based on MongoDB, PostgreSQL etc. and they are helping through Percona Forum. I just need to understand if this problem related with MongoDB itself or something else. Thank you for your kind help already 
@nurlan I am not a DBA but I tried to figure it out, yesterday I spoke with my customer about MongoDB usage and they told me " we are using upsert instead of insert command". After little research at MongoDB upsert commands reflect as “update” commands. So this is explaining my problem. At tests I did not see any insert because upsert is using and it shown as update at PMM. Today I will open mongodb profiler for all queries and I hope, I can catch something.
About PMM 2.14, after upgrading from PMM 2.9.0 to 2.14, all my mongodb metrics gave error. I thought it is because of version of pmm2-client. Then i update one of pmm2-client from 2.9.0 to 2.14 and still I got problems with it. Then it becomes as a bug 
By the way, 2.9.0 node_exporter features works with PMM 2.14 but mongodb not. Thanks 