Systematically first time a docker is launched after being copied from another one fails

[ifoche]

To replicate it:
d2-docker create data xxx/yyy:zzz-a
d2-docker start xxx/yyy:zzz-a
d2-docker stop xxx/yyy:zzz-a
d2-docker copy xxx/yyy:zzz-a xxx/yyy:zzz-b
d2-docker start xxx/yyy:zzz-b

First time xxx/yyy:zzz-b runs, a blank dhis2 will be shown, and no credentials will be accepted. Second time it will show perfectly fine.