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LT1881 vs LT1636 dynamic load

Using the LT1881 as the difference amplifier for a dynamic load.

The output of the Opamp is slammed against the positive rail regardless of the value of Vctrl.

If I simulate the same circuit using an LT1636, like I saw in someone else's design, and the design works just fine. I am at a loss as to why one does and one does not work.

Can someone help me understand?