I used to be very happy with sale_invoice_grouping module, it worked out of the box without any trouble.
For some time now it stopped to do so; I’m not sure whether I unintendendly changed my handling - of this could have occured since an update. Tried variants in handling (w and w/o sales date, valitated or not) but in any case in customer invoices they remain separate.
I’m on v6.0.14 for trytond and 6.0.0 for sale_invoice_grouping.
I checked that, but it’s set to “standard” in the parties in question. Noticed that my productive system was not really up to date due to mistakes in my update script. So I’ll see what happens with the next invoice to be issued.