The first thought I have is you are using a desupported version that no one thought important enough to patch in many years.
If you can move to 188.8.131.52. If not at a minimum patch to 184.108.40.206 (the terminal patch for your release).
Possibly you have hit a bug corrected years ago.
take a look at here:
I think you shall put your connection class and connection purity and it will be fine. About the version and the bugs, I don't think so. You can use DRCP in 11.1. But keep in mind that is good idea to patch and upgrade your database more often