This has nothing to do with d50/d50s. D50/D50s use ESS's integrated digital receiver. D30pro uses CS8416. Same XMOS as receiver which is used by many professional audio interface and fiio. They work fine with good quality spdif signal but not very well with poorer quality signal. Most CD players are pretty horrible in this. The issue is not so simple and not too complicated. D90se uses LC89091 which doesn't have the same issue. And we are trying other chips to see if there's issue.
Are the CD players, receivers etc which demonstrate the problem with the CS8416 out of spec in terms of how much jitter they're emitting?