Google Search Console reports the 'field "id" missing' error in navigation paths for the board index button in the header navigation of prosilver template.
Here the html source it highlights:
It plays btw no role if the default "Board index" is left in place or a custom website link + text is enabled, we get the same errors in both cases.
I have no idea why this is considered an error by GSC since the other breadcrumbs do not have "id" fields either but only for this one case it is highlighted as error. Actual website use is IMO not decreased in any way, so I'd see this as minor issue, probably even a bug in GSC, not sure. Since admins might prefer an error-free SEO report, it might be worth having a look at it.
Wordpress seems to have run into the same, in case it helps I reference the discussion here: https://wordpress.org/support/topic/missing-field-id-in-breadcrumbs-on-google-search-console/