I like that very much. Well taken.

Perhaps I should have added my K-1 is set up to save raw+jpeg to two cards, four files in all. I don't know whether it save the files in parallel or sequentially. I noted my K-3 sometimes malformed the jpegs in burst mode (not that I use that very often) but I might have turned the camera off and back on thinking it had locked up rather than not competed the writes. All the raw files were fine though.
The fact the camera takes so many seconds to save a file doesn't mean another photo cannot be taken before the first write has finished.

The camera puts then in daily folders (sometimes two or more if there are more than 100 images.) Extracting all the files into one flat folder must be a headache to navigate to find what you want. 10,000 files in one folder, whoa!

Six seconds seems normal, My K-1 takes about seven, but it is a larger file.

I just copy the day's folder across to my hard drive and rename it, eg 101_1229 becomes 20161229. You may need to select a different date format in the camera to achieve that as it defaults to the USA way round Bill indicates in his post..
The folder name can never repeat and all the folders list in date order. I then add a suffix as to which camera was used, so the folder name now becomes, say, 20161229_K-3
If I've used several cameras on the day I'll have a second folder with that date and the other camera name combination.

Fair do's, but JL give a two year warranty as well. It seems JL are clearing Pentax items out, they are only showing five products in stock and all on clearance.

As John suggests lens correction could be the issue. You haven't stated which camera and lens(es) are involved so can only guess what it could be. However if it is a newish lens its correction data may have only just been added to the camera's database in the update to perform correction so it might be performing that now when it wasn't before. If you have lens correction turned on, try it without and see if it makes a difference. If it is that it would explain why it only happened after the update.

Just out of interest, are you aware this is a UK based site? We're not generally over familiar with the scene as to your USA repair centres. Reading the US Pentax forum, they do seem to have issues regarding getting repairs we don't and vice versa. Of note was the trouble some on your side of the pond were having getting a problem with the K-1's mode dial repaired, requiring cameras being returned for weeks away rather than being replaced. Touch wood, that hasn't happened to us!

It would be very costly for many of us here to use your preferred repair centre due to postage costs as it would for people on your side to use ours.

I believe it's discontinued so second hand only unless you can track someone with new old stock.

Well done, a happy contented looking budgie! Actually a chaffinch I believe.