If the noise level is being reported properly, that is pretty high considering you are using parabolic grid antennas. What is the gain of the antennas?
The signal is very strong and SNR seems good.
One thing I noticed that that you have your data rate locked in at 54Mbps. Locking it in at the maximum data rate doesn't give the bridges any room to move if it encounters interference or errors.
Allow the device to auto select data rates for the time being and see how that helps.
I see that you are on 2.4 GHz. 2.4 GHz is a horrible frequency, and even worse for PtP solutions. If you do decide to purchase something else, go with a 5 GHz solution. When you decide to purchase, let me know your budget and I'll throw some suggestions your way.
Beyond the info you have given in the post, the next step in troubleshooting would be spectrum analysis and packet capture.
Out of curiosity, where are you located?