Hi.I saved scenario as a file.So you can run it to replicate the issue.
I added side a and side b.
side a have a 055 DDG and some kj500 AEW.
side b have a DDG Atago
you should order 055 to engage with atago and fire yj21.
When the yj21 missile approaches the target, then the missile will stop in ...

I created a scenario and added a few 055 destroyers and Arleigh Burke class destroyers. When I launched YJ-21s to attack, the missiles went to the target but then the game became unresponsive.
I have attached log file with some exception information I hope it will be useful to you.

<type>Update</type>
<summary>Change J-31(carrier variant) to J-35</summary>
<detail>Change J-31(carrier variant) to J-35 </detail>

<t> <type>ADD</type><br/>
<summary>add Shenyang J-15T multirole fighter aircraft</summary><br/>
<detail><br/>
J-15T is a CATOBAR variant of J-15.intended to be deployed on Type 003 aircraft carriers of the People's Liberation Army Navy.<br/>
J-15T has an improved avionics system and equipped ...

<t> <type>ADD</type><br/>
<summary>add Xi'an KJ-600 AEW</summary><br/>
<detail><br/>
The Xian KJ-600 is a Chinese twin-propeller, quad-tail, high-wing military aircraft designed for cargo and airborne early warning and control,intended to be deployed on Type 003 aircraft carriers of the People's ...

<t> Sorry because my account was just registered, so I cannot send any links or pictures.<br/>
I hope hhq-9b can be added to the game, because it has been equipped with the PLAN since 2014,<br/>
but only the early version&#65288;hhq-9&#65289; is added in the game.<br/>
My English is not very good ...