In 1.15.2, I could use /execute to find something within my inventory, however, in the current snapshot, /execute is unable to find it. Here is the command I used in both updates/snapshots.
/execute as @a if entity @s[nbt={Inventory:[

]}]
The Nbt data does not appear to have changed between the two instalments, and no changes have been listed in 20w06a, 07a, or 08a. I am lead to believe that this has been caused by an unmentioned change in slot values or even the way /execute handles nbt data from a player's inventory.
Once again, I used this command in both the latest snapshot and the latest update, which means it was an issue caused between then and now.