1.19.3 Pre-release 3
In some cases, a /data modify command will fail with the new "Resulting NBT too large" error, but an equivalent /data merge command will succeed.
Unfortunately, as of yet I'm not able to work out the exact conditions for the discrepancy, but we do have a repro world!
1. Download and open the attached world
Both commands should succeed
The second command fails with a "Resulting NBT too large" error