Several users have reported positioning offset issues with both enabled. Here's one user, Weissrolf's findings on a workaround:
Weissrolf — Today at 4:58 AM
@Methose @Norc The default settings aligns the bars, but Custon Hotbar is currently not fully compatible with "Monk's Hotbar Expansion". As a workaround, if you use both modules then you need to set CH's "Foundry Hotbar" position to non zero (both X and Y), else it reset the Foundry hotbar to the CH defaults. Additionally you need to add the new Foundry settings on top of CH's own position setting. E.g Foundry Hotbar to 1/1 and CH to 221/64.
Several users have reported positioning offset issues with both enabled. Here's one user, Weissrolf's findings on a workaround: