1 year old ragdoll with soft stool

My ragdoll (Oreo) is just over 1 year old. Recently I have noticed that he has soft stool once every few weeks (usually last 1-2 days). The soft poop would usually have one little pile that is mostly liquid with a little bit of blood (red spots on the poop). I am not sure what is causing it because it just goes away in a day and the stools turns back to normal form and color.

I brought him to the vet almost 4 months ago because of the same problem. We did a stool inspection for parasites but nothing was found. We also did a deworm and got the meds which help to prevent soft stools. But those meds don't really help because the problem goes away by itself a day or so.

I should mention that Oreo still eats and plays normally even when he has soft stools (but he tends to meow a lot after pooping if it is soft stools). Has anyone had similar problems before? Are the blood spots in stools a serious issue?

Thanks

Could be intestinal disease that requires a special diet. We currently have our 6lb ragdoll, Henrietta, on a scoop of Royal Canin ragdoll dry formula in the morning and a packet of Dick Van Patten's chicken and pumpkin wet food in the evenings. We cut up the chunks of chicken in the wet food to make it easier to eat. Perhaps talk to you vet about a special IBD diet? There are expensive tests they can do to see if there is inflammation in the intestine, which can be a serious issue since it causes pain and bleeding.