Preaching

Philippians 1
15 Some indeed preach Christ even of envy and strife; and some also of good will:
16 The one preach Christ of contention, not sincerely, supposing to add affliction to my bonds:

This passage suggests some conflict among the Philippians, possibly involving self-seeking Judaizing, but conflict just the same. I personally, would never underestimate the harm that can come from contentious preaching.

But, in the end, Paul's conclusion is, if they preach Jesus, they are acceptable:

Philippians 1
18 What then? notwithstanding, every way, whether in pretence, or in truth, Christ is preached; and I therein do rejoice, yea, and will rejoice.