There are no end of turn triggers here. The discard to hand size is an action perfomed in the cleanup step. If some trigger goes off or a state based action is performed in the cleanup step, there is another cleanup step after this one.

So you discard to hand size, which triggers the Bag. So there will be another cleanup step. The trigger is put on the stack and eventually resolves, a card is exiled during your turn. This triggers Ketramose, which wil draw you a card. No more triggers so the game moves on, to the now following cleanup step. And the same thing happens, because you have more than 7 cards in hand. Again, and again, and again.

This is not a bug, it is a mandatory loop, and it will end the game with you losing for having to draw a card from an empty library.

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514. Cleanup Step

514.1. First, if the active player’s hand contains more cards than their maximum hand size (normally
seven), they discard enough cards to reduce their hand size to that number. This turn-based action
doesn’t use the stack.

514.2. Second, the following actions happen simultaneously: all damage marked on permanents
(including phased-out permanents) is removed and all “until end of turn” and “this turn” effects end.
This turn-based action doesn’t use the stack

514.3. Normally, no player receives priority during the cleanup step, so no spells can be cast and no
abilities can be activated. However, this rule is subject to the following exception:

514.3a At this point, the game checks to see if any state-based actions would be performed and/or
any triggered abilities are waiting to be put onto the stack (including those that trigger “at the
beginning of the next cleanup step”). If so, those state-based actions are performed, then those
triggered abilities are put on the stack, then the active player gets priority. Players may cast
spells and activate abilities. Once the stack is empty and all players pass in succession, another
cleanup step begins.