Simple virtual column in read only table with delta sync on takes minutes to update

[OptimiX_XcrY]

Hello ,

I have

-a read only table (with delta on,and no security filters applied) , with one column, and 100 rows. The one column contains numbers from 1 to 100 , representing Order Numbers.

-an Orders table, with multiple column, one of the columns being the order number (not a key column).

-a slice that represents Open Orders , with less than 10 rows in result.

-a virtual column in Order Numbers that lists the Open Orders numbers , with some simple Open Orders[number] formula.

This VC does not update instantly and it even takes quite a few minutes to do so.

Is this a recent behaviour change , VC not being processed instantly for read only with delta tables? Is this intended or a bug?

I noticed in the performance monitor a property “not modified: true” for my read only table .

I tested the same formula in a more than 10000 rows table that is not read only. It works just fine, taking less than 5-10 secs.

Thank you.

Edit : i used the same approach a lot of times in the past , for stock inventory, etc ,with succes.