In FMP24, on some frequencies, pressing "I" doesn't actually toggle the injection side, though it says so on the console.
One example is 389.4. If you are tuned to 500.0 and set to low-side injection and then tune to 389.4 by typing it in, it will move to high-side without saying anything on the console. Pressing "I" gives "Injection mode set to high" on the console, but doesn't actually change the side according to the position of the highlight bar in the spectrum display (i.e. it's still to the left of center). If you press "I" again, it says "Injection mode set to low". If you tune back to 500.0, it will move the injection back to low-side (if you attempted to toggle it an even number of times). It does this for the range 389.373380–389.463378.
There are other examples that are wider, like 774.085763–774.373760, which forces low-side.
One example is 389.4. If you are tuned to 500.0 and set to low-side injection and then tune to 389.4 by typing it in, it will move to high-side without saying anything on the console. Pressing "I" gives "Injection mode set to high" on the console, but doesn't actually change the side according to the position of the highlight bar in the spectrum display (i.e. it's still to the left of center). If you press "I" again, it says "Injection mode set to low". If you tune back to 500.0, it will move the injection back to low-side (if you attempted to toggle it an even number of times). It does this for the range 389.373380–389.463378.
There are other examples that are wider, like 774.085763–774.373760, which forces low-side.
