Agree. It's likely caused by frame rate conversion.
Anime like Sailor Moon Crystal is drawn at an even lower frame rate. So from the source to broadcast in HK, more than one conversion is needed. Every conversion impacts the smoothness.
From the source to broadcast, I guess the content may have been converted more than once due to logistics reasons, intermediaries, or standard procedures of the companies and the different departments involved.
Secondly, there are different frame rate conversion algorithms that result in different perceived smoothness. Magic TV used to advertize smooth frame rate conversion from 50Hz content to 60Hz display (for Japan TV and computer monitors).