Reference module strange behavior after Omeka S update

After updating Omeka to version 2.1.2 (from 1.2.) the “Reference tree” block of “Reference” module (V3.4.21) has a strange behavior, as it does not index all existing items (example in https://www.csarmento.uminho.pt/site/s/rgmr/page/n-mero ).
Before the update every branch had several items, but now, only a few of the branches have items (and not all the items it is supposed to show).
Is seems to us that it can manage about 31 item references per block. If the the number is higher only some (ramdom) items are indexed in the tree.

Does anyone have an idea idea of what might be causing this behaviour?

Thank you!

Can you make a screen shot of the config of the block? Thanks.

Hi Daniel,

Here are the screenshots of the module configuration in the page it is inserted:

(This from an example page we have created that can be seen here https://www.csarmento.uminho.pt/site/s/rgmr/page/numero2 )

I have also made screenshot of the configuration of the Reference in the modules pages.

Let me know if you need any more info.
Thank you a lot for your help.