When do passive item rerolls stop working?

From the Missing No. wikia page, it looks like if you have too many items, you have a high risk of just rerolling them all into Breakfast.

If the player has already obtained a large number of items (such as during a run where they have gained infinite money in greed mode), it is highly recommended to avoid this item, as it will almost always end up rerolling all the items the player has thus far collected into Breakfast.

Based on this passage, it sounds like this is exactly what happened. I'm not sure how much health you had at the time you rerolled, but if you had infinite money, I'm sure you had enough items where rerolling them all into Breakfast would appear to have not done hardly anything.

For example, say you reroll 20 items and technically gained 20 Breakfast items, but since you were at 10 red hearts already, it would appear that you only got 2 more red hearts and lost your other 18 items, since the other 18 red hearts don't show up as they surpass the maximum number of hearts you can have.

Additionally, the D4 has the potential to remove your items. From the D4 wikia page:

When the D4 has rerolled through all items it will eventually remove all of them upon use.

Triggering either of these items multiple times on a floor (or even once each) while you have a lot of items has a very high risk of depleting at least one item pool.

The D4 and MissingNo work on all the passive items you've found and reroll them, the fact that you still had to exhaust any item pool doesn't matter here (and by the way, if you started finding Breakfast in the store, it meant that you had depleted at least one item pool).

The fact with the D4 and MissingNo is that they DISABLE all the passives you currently have and give you an equal amount of random passive items; you can see this in Rebith with no DLC: if you pause the game after using the D4, all the items you've found are still there on the post-it in the pause screen, in addition to the new items the D4 gave you. If you had a huge amount of items, you'd be able to deplete every item pool in the matter of a couple of iterations, leaving you with only Breakfast to be found. So you'll end up with 12 full hearth containers and nothing else active.

As other answers suggest, it may be a D4 bug:

Using the D4 too often will exhaust every single passive item in the Treasure Room item pool, causing items rerolled by D4 to become Breakfast. Treasure Rooms themselves may still contain active items, however.

But this behaviour could be due to Chaos, if you have it.
Once you start finding Breakfast you have exhausted at least one item pool. If you picked up Chaos then you have a great chance of finding several Breakfast:

As the item does not actually mix or combine item pools, it is possible to quickly deplete smaller item pools and end up with Breakfast.
Thus, if Chaos tries to pull from an item pool that is already depleted, it will not pull from a different pool and instead give you Breakfast.