Meaning of ともすれば

Question

Reading the first volume of 僕の愛したジークフリーデ, by Matsuyama Takeshi, I found this sentence:

それは、これまでとは明らかに違う怒りだった。単なる激怒や怒声とも違う、ともすれば子供じみた、感情そのままの発露

To give some context, the angry character (A) is dueling with another (B); originally, the duel was due in the past to decide who was to be the new commander of the royal knights, then chaos ensued, B was branded as traitor and (maybe due to that) the duel didn't happen. Then in this occasion B asks A why the duel, since B - being branded as traitor - can't be the new commander anymore. A gets angry, and replies 私がそんなもののを欲しがると思うんですか……ッ！？.

I initially thought that ともすれば meant something like "rather", like "It wasn't just rage, rather it was a childish expression of emotion", but then I found, ともすれば means "apt to; prone to"; can ともすれば also mean "rather"? Should I read that line like "It wasn't just rage, it was a expression of emotion prone to be childish" (which in translation I think would be more natural as just "a childish expression")? Or there is something else I'm missing?

I also found this answer, but it doesn't really help.

Answer 1

I think the explanation you are looking for is actually in that answer you linked, but I see your struggle and I understand why this word's exact meanings are difficult to grasp, so I am going to give it another crack. Adverbs are hard. A lot of adverbs don't have good equivalents in other languages and are hard to explain cross-linguistically. And ともすれば is definitely one of them. The English definitions given by bilingual English Japanese dictionaries are useless in this case, because the "apt to, liable to, prone to" definition is nothing if not confusing. But I'd like to draw your attention to what @naruto says here:

In your examples, ともすれば is effectively weakening the meaning of そうになる

In some cases ともすれば effectively translates as "sometimes" "in some cases" "tend to" or even "may" "maybe" "perhaps". What really complicates the issue here is ともすれば often co-occurs with そう and がち. For example:

現代では忘れられる
Nowadays it is forgotten (by people)

現代では忘れられがち
Nowadays it is easy to get forgotten (by people)

現代ではともすれば忘れられがち
Nowadays it sometimes tends to be forgotten (by people)

As you can see, all these terms are hedge words that weaken the assertion made in the statement. I would render your sentence something like this:

単なる激怒や怒声とも違う、ともすれば子供じみた感情そのままの発露
It was not simply fury or angry shouting either, perhaps just giving vent to childish emotion.