True, its not right. Maybe look closer to home. You might need a ladder.
Probably the aerial has moved a little, just enough, in the wind the other day. Ive had the same problem in the past and fixed it by climbing up on the roof and tweaking where it was pointing. I had the TheWife™ on the end of the phone to let me know when things were better/worse as I moved the aerial. Then when it was all good I tightened the brackets so it'd be less likely to move again.
All 5 muxes are on different frequencies. Antenna will have different signal output on each frequency.