Is it normal to keep quitting Japanese books halfway through?

I’ve noticed a pattern with my Japanese reading lately and I’m wondering if this is normal.

I keep starting Japanese books, making it to around the middle, and then just dropping them. For example, I've been on Kiki's Delivery Service book 4 for a few weeks now and I am just not getting anywhere because it's boring. It’s not that the books I pick are too hard. I can read them but somewhere along the way I lose interest and stop picking them up. Then I move on to something else and repeat the cycle.

I haven’t actually finished a Japanese book in a few weeks now, and it’s starting to bug me a bit. In my native language I finish books just fine, so this feels specific to Japanese.

Is this a common thing for learners?
Is it a motivation issue, a level issue, or just part of the process?
If you’ve gone through this, what helped you actually finish books again?

Would love to hear other people’s experiences.