I believe that it's possible. I've trained like that and had similarly odd results
I have a relatively weak road 5k according to my other prs (I have run a handful of 15:01-15:05s)
At the same time though when event specific fit i've run 3:50 1500 on the track and a few 1:06 HMs on certified course with the same shitty or slighly slower 5ks during that same season but can run routine 4 mile tempos every other week around 20:00 +/- mins in those training blocks
I do the work around 5:00 (or just sub 5) for strength for both distances then either work on 60-62 pace (for mid d stuff) or 5:05-5:10 (for HM stuff) for specificity and it works out that I can PR in the over and under distances but just struggle in that mid range for lack of specific work there.
She probably just (like me in those blocks) isn't doing a ton of work in that 3k-5k range so shes not super comfortable there or going under that. Thats really it.