I've had this come up and both legibility and authenticity are extremely important. I would make the text into the one bubble and simply place it in the center as much as possible. No reason to erase anything and make it look like it was supposed to be one bubble.
I can't see your example pictures, but for my project there were many instances of a line starting in one part of the bubble and ending in another. For this, I just broke up the line accordingly. For example:
First part of bubble: I
Second part: love you.
It's still seen as one line despite being separate because of the wonderful law of continuity. ....or continuation... *not an editor for a reason*
Of course, there's also the issue of having teeny, tiny text when a long horizontal English word isn't fitting into the very vertical and narrow bubble. A lot of people (mostly in scanlations or early released volumes) will "stack" the text. The only time stacking text is acceptable is for a sign with one, maybe two, words. Such as "OPEN" or "STORE NAME". Dialogue shouldn't be done this way (I'm sure there are exceptions to the rule, so I don't want to say anything definite.
To deal with this, just *grumble* hyphenate and put a white stroke. Yeah, I hate hyphenating. lol But hyphenating is acceptable and much more legible than stacking text.