Questions: Girl's Behavior

So I’ve been texting with this new girl from work for about 2 weeks now. We text every day and the contribution to the conversation is equal (she will text first as much as me, and she will talk as much as I do).

I noticed last night a pattern that I’m concerned with. We will have very brief conversations during the day when I reply to a meme she sent or vice verca, but that’s it. Neither I nor her have ever texted anything like “how are you” to each other to start a conversation. Also with big gaps in time, like she will take an hour to respond, and then of COURSE I have to take an hour to respond too. This is mostly how it is during the day. Subpar.

However at night, really anytime past 7pm, we have a fluent text conversation that might persist for hours. This has been every night for 2 weeks. Suddenly her replies are instant and of course I reciprocate that so it keeps going. Or if she texts first she will just randomly send me something that happened to her or how she’s feeling about something, except only at night! Anyway as I said we both engage in conversation equally, there’s no disparity where one of us is pulling more weight. I’m simply concerned that it looks like she only cares about conversing properly during late hours when she’s bored.

What do you women think, is this a sign that #1 she texts me out of boredom, and #2 she isn’t interested in me?