Background in columns are not working in multisite

Hi, we use the row block of Qubely in a multisite envirenmont. On the subsites we have put a background image on the row (works fine), and a background-color (or image) on the column.
The problem: the column background is not visible on the front-end. Strangely enough the column background is visible in the backend.

When we simulate the same column on the parent site of the multisite, then everything is working fine. So, looks like an issue with subsites in multisites. Thanks for the support!

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