From S02E10 of The Quintessential Quintuplets
Above, we see that Miku is working part-time at some bakery. Yotsuba is visiting Miku at the bakery where Miku has just started working part-time. Miku's seniour colleague refers to Miku as Nakano-san when talking to Yotsuba about Miku's initial failed cooking/baking.
Below, a few seconds later in the episode (which I guess is maybe an hour later in the characters' time), the seniour colleague addresses Miku as Miku-chan when Miku does a little better in the cooking.
This is not just the subtitles. The dialogue really says this. Ah here I found something on youtube: See for yourself from 11:40 to 12:15.
Question: What's up with this? Is Miku's seniour colleague really referring to Miku so differently from addressing Miku? Is the time skip here perhaps actually not 1 hour but several days (and so Yotsuba actually visits Miku more than once) ?