MR Pipelines Tabs is confused about the pipelines total number

Summary

When many pipelines have run for an MR, the number showed in the tab behaves inconsistently while navigating. A clear description of the effect is showed in the video.

Steps to reproduce

One way to reproduce:

• go to an MR with many pipelines run (e.g. this one)
• on page load, the number of pipelines number is 44 (at the time of filling this)
• once the frontend kicks in, the pipelines number is 30

Additionally, navigating through pages shows a different number (video attached).

navigation	landing
Screen_Recording_2021-01-04_at_09.04.34	Screen_Recording_2021-01-04_at_09.58.07

Example Project

What is the current bug behavior?

The number of total pipelines run is inconsistent, changes while navigating the pages.

• page 1, the request returns a count of all: 30, the tabs displays 30 while the pipelines are actually 20
• page 2, the request returns a count of all: 14, the tabs displays 30 while the pipelines are actually 20
• page 3, the request returns a count of all: 0, and displays 14, while the pipelines are actually 4

What is the expected correct behavior?

The number of total pipelines run is inconsistent, should not change upon navigation of pages.

Relevant logs and/or screenshots

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
`sudo gitlab-rake gitlab:env:info`)

(For installations from source run and paste the output of:
`sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production`)

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)
(we will only investigate if the tests are passing)

Possible fixes

The all should probably reflect the total numbers whereas the current number for the page can be just derived by the pipelines array length in the response.