I tried using Pearson batteries that I used in MY GRD4 and brand new Wasabi batteries and neither will seat in the new GR. It seams the the cutouts on the batteries aren't long enough.
The GR uses model DB65 batteries. Generics fit fine as long as they are direct replacements for the DB65 the GR uses. I'd expect DB60's to fit the GRD4 but not the GR, maybe yours are DB60 replacements?
It's just how the GR is designed. Ricoh engineers apparently found the DB60 too weak for the GR? Or maybe they thought that the existing DB60 batteries from previous GRDs are too old (and even weaker) to provide stable power for GR? As far as I remember, this DB65 limitation is not limited to just GR? I believe one the of the latest waterproof/tough models accepted DB65 but not DB60.
It seems the Chinese battery suppliers are quite bemused. Price is not a guarantee of "will fit" or "better". Compatible with db65 helps but db60/65 is listed as well. I think the clones are all much the same, just different sized notches, but there is a need to check as the suppliers are just as confused as we are.
I had some AUD$3.50 (post free!) batteries on the way from China when this issue first came to light. Luckily they had the "long" db65 slots. They seem to work fine. No overheating, no case distortion, drive the camera fine. Have not "counted the shots" but a charge seems to last long enough for me to be happy.
I did worry that batteries that were so cheap would in themself be risky. So I bound them together with marking tape and marked them identically with a painted line. At the first sign of trouble I could dump the lot.
So far so good, and the marked batteries are working just as well as some more expensive ones that I bought at the same time.
The old adage is "if you can't be good be careful".
I ordered some wasabi from amazon that were listed as DB65 but didn't fit. Then I checked the listing and the actual photo showed NP50 on the sticker, which actually matched what was on the received battery. Same exact size, different cut out, doesn't slot in.
Back they went, and this time I payed attention the label in the picture to be sure it said DB65-- got 3, they work great.
They also fit the Sigma DP2 series, which is quite helpful.