If the correct amount of pad is not exposed at the edge of the part, the solder will have nowhere to form a fillet which is critical to its physical attachment.

If the correct amount of pad is not exposed at the edge of the part, the solder will have nowhere to form a fillet which is critical to its physical attachment. Solder is not glue, and even with more pad contact beneath this is a physically weaker connection which often results in tombstones like pictured in TFA. If you read the integration documents for these packages, you'll see that they distinctly specify the requirements for these margins. Probably the length is the more important axis and may be what he was referring to when saying "large". I've seen this be a problem particularly during the "chip shortage" where jellybean parts like these capacitors have the weakest specs in a design, meaning unilateral substitutions can happen at many points in the design/mfg pipeline. Indeed brittle solder is a real phenomenon which is often easily visible in hand soldered joints that we call "cold" joints. Formation of bubbles can happen for a number of reasons, but IME it's the result of low quality solder or flux/cleaning. The organic compounds gasify in the heat and form an internal structure similar to bread. ETA: an interesting paper exploring the cause and minimization of voiding in the reflow process. Particularly, the decrease in thermal conductivity in voided solder can critically contribute to its failure in high-heat operational environments. https://www.circuitinsight.com/pdf/controlling_voiding_mechanisms_reflow_soldering_process_ipc.pdf https://www.circuitinsight.com/pdf/controlling_voiding_mecha...