I answered earlier today but being new to the forum, I probably didn't do it correctly but am now properly joined, so here's hoping this gets to you. Did you get any resolution to the problem with your LG Tv.?
My 55 inch Lg smart Tv, bought in September 2018, is doing exactly what you describe. Both ABC and SBS stop repeatedly. Other things such as YouTube, Netflix etc are ok. It is clearly a TV issue as desktop computer ( ethernet) and ipad and phone (wifi) work fine on both of those sites. I asked our local Facebook community site and someone said they had the same problem. Sounds like they didn't resolve it.
I don't think I have any chance with LG as it is out of warranty. The screen was recently replaced under a 'good will' extension of my warranty and the problem has worsened since that repair. I will call the repairer and see what they have to say, but am not hopeful. Looks like I got a lemon!