Yes, I do notice that intermittent frame freezes on Showcase Movies channel, and it occurs at any movie/showtimes, so you're not alone about this.
From the way I see it, it seems there's some video encoding issues on their side. And certainly there's nothing wrong with your Astro box or satellite dish, so don't worry.

If the person-in-charge for monitoring the channel is seeing this post, appreciate if you could spend some time watching movies on Showcase Movies channel over linear TV platform (not via On Demand platform, obviously), then you'll know what we meant.
I also notice tvN channel (395) has intermittent pixelation too, and it's already been months.
The kind of pixelation that looks like marginal satellite signal/network packet loss, not the poor-video-quality kind of pixelation ya.
And yes, I do notice that pixelation at that same point of broadcast time even when I watch it from Play from Start / Live Pause, so definitely it's not satellite dish problem.
If I complain to customer service, then we'll have to go through those irrelevant troubleshooting steps, suggests that it's my Astro box problem and ask me to reboot my Astro box and whatnot
So I rather just ignore this issue, and let other more concerned/furious viewers to make noise to them instead.

I 'think' we are talking about the same freeze, because I also face those weird freezes in Astro Vellithirai too. It is something like pixelation and the movie just stops for a short millisecond. Thought I'm the only one but even my sister face the same thing too.