Getting random LCK_M_SCH_M on convert and bulk insert task

I starting getting random LCK_M_SCH_M locks with huge wait time, which hung my etl proccess.

The ssis package runs like this:

I have 4 containers that run in parallel and do the same thing:

-Convert a tab delimited file from unicode->utf8
-Truncate the table (within a foreach loop)
-Bulk insert the data

Also transactionoption is set to NotSupported.

What could be causing the lock?

All foreach loops do not overlap ragarding tables/files.

Do they contest somehow?