I have played with different libraries (4.14, 4.16. 4.16B, 4.17B), Delfmem, and Delfinit. I haven't found the magic combination to make it perfectly (or real close to it) stable yet.
I don't have Delfina anymore but if I remember correctly, the problem seemed to be in the DSP system software, in the multitasking / time-sharing part. It locked up very easily.
Disabling Delfina's Watchdog helped, but it didn't solve the problem.
You could try DelfTweak. You can increase DSP's internal clock cycles with it, which may help. I wrote it for Delfina Lite so I don't know how it actually affects on Delfina Plus. However, Delfina Lite and Plus have the same DSP so it should work.
