There have been occasional reports of high memory usage when keeping blue ocean open in a tab for many many hours. 

It isn't clear what page yet, but it is worth investigating: 

• Dashboard main page
• Activity page for a given build

Ideally in cases where there are running builds. What should be noted is if there is monotonically increasing memory usage for the tab. If there is - likely candidates are SSE events loading data into a store (something like mobx) which probably should be more of a buffer...