Troubles with the Content Not Permitted error

Hello! Ever since mid April of this year, I have been using Gemini 2.5 Pro and Flash, mostly for creative writing/story generation. I must say that Gemini 2.5 is a very good model for story writing. It can generate long and detailed prompts with a good quality, as long as you give it a good enough prompt. However, there is a major issue I have with Gemini, and that is the dreaded "Content Not Permitted" error.

Many times, when writing a prompt for a story (usually the next chapter), the content not permitted error appears. If it appears before any text is generated, any other message sent after that will result in another content not permitted error no matter what, but if it happens during text generation, the prompt can be continued.

For example, if I got the error during a chapter generation, I could simply write "continue/finish the chapter" and it would finish it without a problem.

However, when I entered a prompt for the next chapter into Gemini and got the error before any text was generated, I simply couldn't continue with the chat no matter what - even if I simply asked Gemini "what's wrong with the prompt?", it resulted in another instant content not permitted error. The only way to continue the chat in this case is to find the part of the prompt responsible

Why does it happen?

The most frustrating thing about the "content not permitted" error is the fact that it's extremely unpredictable and random. Literally ANYTHING you write into the prompt can trigger the error, even completely innocuous words with ZERO illegal/inappropriate connotation.

For example, today I was writing a prompt for the next chapter of a horror/fantasy story, which contained a description of the main male character and his tomboyish girlfriend's adventures in the forest. The prompt contained a description of a somewhat explicit scene where the main characters get undressed (including a joke about the girl being flat-chested) and have fun bathing in a waterfall before discovering some ancient catacombs beneath it. What's interesting that Gemini didn't block the prompt with the "content not permitted" error because of the undressing scene, but because of a much more innocuous part of the prompt when they simply play in the waterfall and pour water on each other for fun.

That's right, Gemini had no issues with a joke about a tomboyish girlfriend's flat chest and an undressing scene, but blocked the prompt because they... playfully sprayed water on each other in the waterfall? I'm honestly very surprised that THIS was the reason the prompt was blocked. I thought it was because of the more explicit scenes, but no, the explicit scenes were completely fine with the AI, and the actual reason for the error was simply one paragraph which said "they had fun in the waterfall, laughed and sprayed water on themselves playfully", despite the undressing/flat breasts joke scene being MUCH more explicit than this.

Another funny example is a later scene in a much later chapter, where the main antagonist (a dark wizard) was discussing a slave revolt in the mines of their tower. The chapter contained description of violence and fighting, including a scene where one of the main characters gets almost killed by monsters - all of these were completely fine with the AI, none of them triggered the "Content Nor Permitted" error. What DID trigger the error, however, was a short scene where the dark wizard's sister, a dark witch, mentioned descending to the mines to deal with the slave revolt herself - which again, is a MUCH less explicit scene than a scene where a character almost dies because of monsters. But somehow, the former was what triggered the error while the latter was not.

I honestly don't get why does this happen sometimes - certain words or sentences trigger the "Content Not Permitted" error seemingly out of nowhere, while other parts containing MUCH more explicit content are fine and do not trigger it.

My theory is that the way Gemini's censorship filters work is that, if you enter a certain combination of words, it increases the change of triggering the filters despite the content being completely fine, even with more explicit content.

I'm curious, did you experience the same strange issues as me, where your prompt was blocked by the dreaded "Content Not Permitted" error, and you had to remove seemingly completely random/innocuous parts of the prompt to solve this, while the more explicit parts of the story were actually completely fine and NOT the reason for the blocking? I remember one person here saying he had to edit his prompt to remove the word "nurturing" from a prompt because that was apparently what triggered the filter, so I'm curious if others had the same/similar issue as me.