It seems to me that in AmE the diphthong in cold, colt, hold, mold, sold & told is often (or always?) either too short or absent altogether unlike in words like rose, hope, poke, tone, boat and so on. The dictionaries that I have access to do not mark the audible difference I'm encountering.
Is this the effect of the following l/ld/lt sounds? Or is it something else? Is there more to it (e.g. somewhat similar "anomalies" neglected in dictionaries)?