Shadows disappear when 30> (foliage) Trees

Hi all,

When scattering trees (about 9m tall), I can see their shadow when there are few tree (like <30) and then, I can only have the contact shadow from far away, but no shadows nearby. Using Lumen in UE5EA.

Strangely enough, I do not have this issue with small props such as flowers or bushes.

Have you had the issue and if so, how did you solve it?

The best option I found is to place meshes individually, not using the foliage tools. It works fine.