I won't claim to know more than an engine manufacturer, but, turboprop engine mounts are often statically determinate to keep structure weight down and thermally isolate the engine.
The down-side is that all mounting points are necessary to keep the engine in-place. A failure in any one point allows a line of rotation to form about the remaining mounting points and the engine can move enough to cause the remaining attachments to fail if ignored.
Turboprop engines "breaking away" go back to the Electra and was suspected by ALPA as the cause of a
1991 accident involving a 1900C. In fact, Conquest Airlines had enough difficulty with downtime for repairs to their 1900Cs' engine mounts that they eventually sold them all and bought Metroliners.
So there is an engineering push in opposing directions to make an engine mount as "insubstantial" as possible while still being strong enough to hold the engine for all reasonably conceivable conditions.
As far as intentionally designing engines to breakaway, I don't know.
There do seem to be lots of patents for lighter methods for hanging turbofan engines from the wing structure. It's probably the same situation: the push for lighter weights and ease of maintenance has made the attachment point evolve in a way that they are not intended to be strong against abnormal loads (outside of reasonable and certifiable, at least).