Hi @Tanguy Crusson and community,
"Linked Issues" (upper case I) is a Jira field which has been around for many years. It displays the keys of issues linked to the current issue in a Jira filter report.
"Linked issues" (lower case i) is, as far as I can tell, a relatively new field introduced by Jira Product Discovery. This field displays the number of issues linked to an idea.
Having two fields with almost identical names (with wildly different semantics) is something that most Jira admins recognize as a bad idea, and they wouldn't allow it on their Jira system. Thus it's very surprising to find that this "worst practice" was implemented by Atlassian. I would argue that this is a bug, but in any case, Atlassian has taken it as a "Suggestion", JPD-124. If you'd like to see this fixed, please watch it and vote for it. And Tanguy, would it be possible to open comments on the JPD project?
Thanks,
Kel