I have 3 dashboards in a folder. I add a 4th one, one of the 3 disappears!?

I already have 3 dashboards in a folder.
They look fine, get updated. No problem.

I add a similar one. But there are still only 3 dashboards!
It looks random which one is being dropped.
I retried making sure the ids are unique, both for the dashboards and the panes.

vade> grep -r '"id":' deploy/grafana-dashboards/
deploy/grafana-dashboards/vade-gen.json:  "id": 4,
deploy/grafana-dashboards/vade-gen.json:      "id": 46,
deploy/grafana-dashboards/vade-gen.json:      "id": 42,
deploy/grafana-dashboards/vade-spec.json:  "id": 3,
deploy/grafana-dashboards/vade-spec.json:      "id": 31,
vade> grep -r '"id":' ../openphish/deploy/grafana-dashboards
../openphish/deploy/grafana-dashboards/openphish-gen.json:  "id": 5,
../openphish/deploy/grafana-dashboards/openphish-gen.json:      "id": 54,
../openphish/deploy/grafana-dashboards/openphish-gen.json:      "id": 52,
vade> grep -r '"id":' ../zvelocat/deploy/grafana-dashboards/
../zvelocat/deploy/grafana-dashboards/zvelocat-gen.json:  "id": 1,
../zvelocat/deploy/grafana-dashboards/zvelocat-gen.json:      "id": 12,

At this time, the last one added was openphish, and zvelocat disappeared!
Earlier, I experimented the loss of one of the vade dashboards.
Any resource I can enlarge to allow to display more dashboards?

Problem found and fixed: some clashes in uids (I checked only ids…)