I got it well reproduced (with non-empty http1.0 by interim switch from 8.6, no idea why it has not been removed by fossil).

Fixed in [/vdiff?from=ab484359285cb7c1&to=6c4886e1e14f67e4|[6c4886e1e1]] now and can be closed IMO.

<i>(related commits [59607dfd9e]..[6c4886e1e1])</i>