Three common causes.
Open draft quote
Quotes already in draft don't auto-refresh prices when the catalog changes. Open the draft, re-pick the line item, save.
Wrong currency on the quote
If the quote uses a different currency than the one you just edited, the system shows the price for that currency, not the one you changed. Edit all currency variants if you want a global price change.
Browser cache
Rare but real: reload the page hard (Ctrl/Cmd+Shift+R). The picker may be showing a cached catalog from minutes ago.