Kibana stack monitoring graphs is not clear

I upgraded elasticsearch and kibana version from 7.5 to 7.12. I have seen unclear stack monitoring graphs after the upgrade process. I don't understand why it happens. I added screenshots. Can you help me with why it happens?

Welcome to our community! :smiley:

What do you mean by unclear exactly?

Thank you for your message :grinning:
I mean, the graph line is not continuous, so there is no value at certain intervals or moments.( i.e between 18:16 - 18:18, 18:19 - 18:20, and 18:24 in my shared graphs. )

Ok, just wanted to make sure that is what you were querying.

Is there anything in your Elasticsearch logs at those times?

I couldn't see any error/fatal message in elasticsearch logs, but I saw the following errors in kibana logs. I don't know if it has something to do with that.
Kibana shutdown once in a while, but elasticsearch doesn't.

FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory
1: 0xa04200 node::Abort() [/home/cassadm/kibana/bin/../node/bin/node]
2: 0x94e4e9 node::FatalError(char const*, char const*) [/home/cassadm/kibana/bin/../node/bin/node]
3: 0xb7978e v8::Utils::ReportOOMFailure(v8::internal::Isolate*, char const*, bool) [/home/cassadm/kibana/bin/../node/bin/node]
4: 0xb79b07 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, bool) [/home/cassadm/kibana/bin/../node/bin/node]