jpeg not being added to catalog on export

hi, i'm new to lightroom classic and when i began using it ,  whenever i exported an edited file LR would automatically add a new jpeg (of the edited file) next to the raw file in the "film strip" at the bottom of the screen.  Now it's stopped doing that and i can't figure out why. I have checked the box in preferences to "treat jpeg files next to raw files as separate photos" but it makes no difference. my edited jpeg files are being exported to the export folder i choose. i will really appreciate help with this. TIA