Geolocation
By default, the booking engine will attempt to predict the currency you wish to use on the booking engine using geolocation software based on your IP address. The aim of this is to enhance the chances of visitor conversion on the booking engine.
While geolocation software is normally accurate, it is not 100% accurate.
There may be the odd instance where it reports the location of someone incorrectly.
Currency changed
You may have changed the currency at some stage on the booking engine and the system is remembering that choice.
In this case please choose the currency you want to see and hit Ctrl and F5 on your keyboard to clear any cache and background references to the other currency.
Internet service provider (ISP)
If your internet provider is using a server from a different country and is assigning you an IP from that server, or your internet access is going through a proxy server in another country, the booking engine will pick up the IP and predict the currency from that country.
If you wish, you can email support and ask to have currency prediction disabled for your booking engine.
This does mean that guests from any country will only see the prices in the properties local currency by default.
Discuss with support before doing this as it may impact conversion.
Hardcoded links
There are hardcoded links on your website or ezine that force a specific currency to show.
You may have accidentally grabbed a link to a specific rate with a currency already set on the link and promoted it on your website or ezine.
This means that when the link is clicked, it will force the prices to show in that specific currency.
In this case contact your website or ezine designers and ask them to remove any code that sets currency in the link.