EDIT

Normally the bibliographical authors are also nomenclatural authors who designate types, so far no problem.
If a treatment is made by section authors (e.g. nomenclatural authors of a new combination) and a typification is part of this treatment (without mentioning the authors again), it can be concluded that the section authors are also the typifying authors.

Example: http://phycobank.org/102043
Adlafia tenuis Van de Vijver et Goeyers in Van de Vijver, Haan & Goeyers.
The types are published in Van de Vijver, Haan & Goeyers (This is correct within the registration page).
The name page reads "Lectotype (designated by van de Vijver, B., Haan, M.D. & Goeyers, C. 20191): Chile, Grundschlamm des Teiches auf der Dachstein-Westplatte (KASSEL D III 163/4263)."

I think, it should be also Van de Vijver et Goeyers in Van de Vijver, Haan & Goeyers.

This is a report to discuss, because a change would make PhycoBank more complicated.

One possibility was to change the output slightly (and give credits to designating authors in a public note):
"Lectotype (designated in van de Vijver, B., Haan, M.D. & Goeyers, C. 20191): Chile, Grundschlamm des Teiches auf der Dachstein-Westplatte (KASSEL D III 163/4263)."