Gitlab CI stage finished, but next stage takes too long to start

Refer to the picture below, the step in gitlab ci seems completed due to Job succeeded within 2 mins. However, this job is completed when 5 mins 27 seconds. I’m not sure why it is but it occurs on every job in gitlab CI. Do you have any suggestion ? (Previous month, it stranged that this stage is completed with 1 mins but after we upgrade memory of gitlab server from 4 GB to 6 GB and finally we got this problem)

GitLab Server = 13.5.3 (Self-Managed Server)
Git Lab Runner = 13.5.0, 13.8,… (we have 4 Runner)