How to use ILA cross trigger for AXI?
The ILA grabs a single window of data for each trigger that it sees. So once the first one has happened, it will not collect any more data after the end of that window.  If the second transaction does not come along within that window then you will not see it.

If you set the number of windows to '2' (or more), you will see both transactions as connected to separate triggers.  However, now you have no idea how big the time difference between the two triggers was. And you get less data in each window :(

Another way to use the tool which is sometimes handy is to set the window length to a single sample and have (for example) 1024 windows of 1 sample each. Then set the trigger to be on any interesting signal change. You will then see all the changes in these signals.  You lose all the timing information, but you have the ability to see lots of transactions, which is sometimes the more useful thing to see.