Does anyone know if this Panasonic TV fault will get worse over time?

Take the refund, then buy the same TV from a different retailer:

https://www.electronicworldtv.co.uk/48-panasonic-t...

http://www.electricshop.com/panasonic-tx48cx400b-4...

That particular TV has been discontinued, which is why it's hard to find.

Vestel is a Turkish manufacturer, which makes TVs for a variety of companies.

3D television was just a flash in the pan (again...). As the demand for 3D has subsided, fewer televisions are made with 3D capability.

It's not possible to predict the future of that fault without correctly diagnosing the cause.

But it won't fix itself and from long experience of working for a TV rental company there's far more chance of it getting worse than of staying the same. At the company I worked for (Forbes Direct) what you're seeing often turned out to be the result of a TV having been dropped onto a hard surface.

If it helps, I have virtually the same TV but in a smaller screen size (also made in Turkey), and mine was a clearance bargain from Richer Sounds. I didn't buy it for the 3D but as it was there invested in a couple of pairs of active shutter glasses. So I can assure you that if you replace the TV with a non-3D model you don't be missing much. The trouble is that the few films with good 3D really haven't been very good films (e.g. Avatar which doesn't stand up to repeated viewing), and the good films with 3D often haven't worked out how best to use it and mostly are 2D to 3D conversions. The problem with that is that everything looks like a load of cardboard cut outs as each 3D layer is utterly flat. There are good 3D films but most are CGI animations and mostly for children, but as animations they then lack the image detail which HD shows so brilliantly. The result is that I've used my 3D glasses about half a dozen times over the last five months and not at all since Christmas. The other problem is that if you wish to avoid noticing the flickering lens effect then you really need to view with the curtains closed and all other lights off. Finally, even when you are viewing a rare good movie with good 3D which isn't a cartoon, then after the first few minutes of "Gosh! Wow!" you stop noticing it apart from occasional special effects. And that's kinda the point: if a film is well-made and has a great script and plot then you get so lost in it that 3D becomes irrelevant.

So my suggestion is this: take the TV back for a refund or exchange or take a big gamble on getting the fault diagnosed and fixed, but there's no guarantee it can be fixed and once you've paid someone to fiddle around inside you cannot return the TV. Personally, I'd take it back.

One additional point: UHD/4K is also pointless at any screen size below about 56" as you cannot see the difference between that and regular HD at any distance which allows you to easily and comfortably see the whole screen. Again, I didn't buy my TV for the 4K, but it's there anyway because marketing departments know that it's an added feature which sells TVs. The downside is that it results in far more image processing within the TV so there's far more chance of seeing digital image artefacts than with a really good regular HD TV. You also cannot use the UHD/4K feature unless you pay extra for a 4K source and they're still relatively scarce and as most are delivered by streaming you need a really fast and reliable broadband connection. My connection maxes out at 8Mbps which is fine for regular HD but totally insufficient for 4K. Ideally and for reasonable download times you need at least twice that and even more if you have other household members using broadband and downloading games, or streaming music or video content.