In my 10, I get moderately low fuel pressures in the climb in hotter ambients; Never on cooler days and always in the later part of the climb where temps are rising due to the thinner air. In the 6, I get this very ocassionally. In both cases, the boost pumps makes it normal. Boost pump is in the fuse, so not heat affected.
I believe that the reduced cooling air flow is allowing the fuel to get too warm and creates some vapor and the resulting disturbance in the suction side of the mechanical pump causes reduced flow and therefore the lower pressure. Have NEVER seen it other than the climb in warmer air.
In my case, I don't believe it is worth remediation efforts, as the pressure never drops below what the servo can live with (around 12-13 PSI). I have heard that 90* fittings (excluding the AN fittings with long sweep tubular structures) or other sharp changes in direction can increase vapor production when fuel is near the boiling point, but cannot comment on how true or valid that is.
Larry