Recently I glued together some laser cut pieces of Acrylic with patchy results.  The bonding was good but the Acrylic cracked. Hundreds of tiny cracks all along the cut edge.

So, what does one dot o prevent this?

The manual states to temper pieces for 2 to 4 hrs at 70°C (≙158°F) to prevent stress cracks. I never assumed that cutting Acrylic with an laser cutter made the cutting edges prone for stress cracks and thought I was applying the glue wrong.
Since everyone told me that these cracks aren’t normal I tried this tempering stuff and put some test pieces for 30 minutes in an oven. Even this short tempering period reduced the amount of cracks by 100% :-). I don’t know if this short tempering time has negative long term effects. If crack form in the future I will let you know.

Long story short or TL;DR

When using a laser cutter to cut Acrylic temper them in an oven.