TRIAC and Driver is heating up
When you use Quadrant IV, it requires much more Ig which with 1k series requires more line voltage and thus switches with more transient loss. A 60W appears as a 600W load when cold.

To reduce Pd in Triac

Thus I suggest you verify ZCS is ok then swap pins on U5-4,6.
 You can remove the snubber for this snubberless Triac part.
Ref

This fix should also reduce heat in MOC, but to improve heat rise further...

To reduce heat in MOC

Ir=(3.3-1.3)/(20+25)= 44mA  which is excessive for 25 Ohm 3.3V drivers. (57mW is 57% of 100mW spec @ Tj=125'C) Therefore design for 20mA.   Rs=(3.3-1.15)/0.02A -25ohm driver= 82 Ohm.

I assume you are using a uC with 3.3V logic equiv to  25 Ohm RdsOn nom.

Observations


This design is far from optimized using 1W resistors when it can be done with 1/4W easily 
Worst case Tolerance calculations are essential for production to factor all variables.
3 Quadrant Snubberless Triacs need to be used in preferred quadrants I,III especially when driving motors due to BEMF.
Pulse mode trigger is far more efficient than linear analog mode for triggering due to lower losses from ratio of Igk^2/Rgk yet Rgk is never given in datasheet.
Simple method uses DIAC with cap discharge, otherwise SMD pulse transformer works best for precision triggers at low phase angle. Then you can discharge higher pulse currents yet short T so low energy.


REF Triac Technology
[How to design Pulse drive]