Tabs missing in simulation

One concern, your file has a Stock Thickness of 1.5 inches:

and you are cutting out a slot which is 12 times deeper than the diameter of the tool, resulting in a very high tooling engagement (assuming your tool has at least 1.5" of cutting flute length, if not, it’s rubbing which arguably is worse) — where possible avoid slotting and add geometry and cut as a pocket

and/or

and consider leaving a roughing clearance and taking a finishing pass.

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