Artifacts on the objects in the scene

Please tell me because of what appeared here such artifacts and how to remove them:
5249e0ff399832c993c0a787c8d70268ede26cb6.jpeg
9c6d6f48c89ed44a036f3d86868dc3e0c3e91b81.jpeg
dc207d6eef4dbd730356db0d3cbe62846be122a0.jpeg
d4c239fe18b2ffd905476a4502a12050e12efb18.jpeg

Thank you in advance for your reply.

Hi there,

Can you show the 2nd lightmap channel for these meshes?

Also are there any meshes that might be there but is ‘hidden’, and UE4 is baking in the shadows which causes these artifacts?

2nd lightmap channel for these meshes:
5a10af73b3b1c7a264f7ae9e71cc134b32595560.jpeg
2e70206961b7e529344b34013c98fc71a23ba6ae.jpeg

Hidden meshes missing.

In other scenes on these meshes do not have these artifacts.

Another such moment:
bf5f25c64528581a56f6f1149b6fb8d2591bcd5a.jpeg
78421fcaf6bdf516fd166e644cea7b79ebfaa9aa.jpeg

Maybe edit the project settings?

Scene: Dropbox - Error
Map titled: Overcast_m_002
TEST_LIght\Content\Maps

The map does not have these problems Flat_0153_m_002

Solved a problem! In Lightmass settings changed value “Indirect Lighting Quality” to 10