Bug in my PS site, any ideas ? Related to shipping issue.

[BlizzardUK]

I have a PS 1.6.1.24 website with third party theme and there is a bug on either the theme or within PS code, I am presuming the theme. The theme developer is unable to help as they say it is not their theme at fault. However I am not sure what it is then, as obviously if this was a PS issue surely others would have this issue, and I can not find anyone else with this problem.

I got a bit hopeful when I was advised there is a recent (summer 2019) 1.1 version of the 1.0 theme I am using, but after checking it the 1.1 zip file it contains identical files to 1.0, even the changelog still says 1.0 and all files are dated 2017. If I was a cynical person I would presume this may have been done to make it look newer on the product sale page (making it show 2019 instead of 2017). Or maybe there is a more innocent reason, such as a mistake in the listing.

Anyway, the bug is that when a customer, who has more than 1 address in different postage zones, changes that address on the checkout, the shipping cost changes to "free shipping!" and the carrier doesn't change (we don't offer free shipping). However, if they then refresh the page the carrier corrects itself and the postage becomes correct. So for example, let's say I have an address in the UK, if I change this (on the drop down address chooser on the checkout) to mainland Europe or America (or any other country) then the above mentioned bug happens. It does NOT happen if the customer changes to an address within the same postage zone. So changing France to Germany, for one of many examples, would not trigger the free shipping bug because it is within the same postage cost zone (EU).

A very good PS expert looked but was unable to work out what was causing it, we hoped changing from 1.6.1.18 to 1.6.1.24 would solve it, but it hasn't. So we are a bit stumped. I realise this error is not too major, as not many people have multiple properties in different countries, but we get 1 or 2 customers a month who do it is annoying enough to try and fix.

I can show a video of the error if it will help, but the above probably describes it well enough.

Any ideas or suggestions on what I can try ?

Thanks all.

[PrestaHeroes USA]

I recommend contacting a PS agency, they will find/solve the problem in short order.  No offense but your PS expert is not very expert to not have solved.  

[Simonas Invertus]

The first questions that comes to mind is: do you use standard PrestaShop check-out or do you have one page checkout module? 

From PrestaShop perspective: it chooses default carrier in case it doesn't know what to show, so this is when free shipping comes out in most cases. If you have no free shipping carrier (even if it's disabled), there is no way PrestaShop could choose it. It comes to two possibilities: theme (as you said) or checkout/shipment modules. To understand what is happening, you need developer to investigate it.

So my recommendation (maybe not very helpful) is to hire a freelancer or professional agency, there is no way to solve this issue without looking at the code. 

[PrestaHeroes USA]

"A very good PS expert looked but was unable to work out what was causing it, we hoped changing from 1.6.1.18 to 1.6.1.24 would solve it, but it hasn't. So we are a bit stumped. I realise this error is not too major, as not many people have multiple properties in different countries, but we get 1 or 2 customers a month who do it is annoying enough to try and fix."

he is NOT a PS expert, that's horrible advice.....

stop using who ever it is...they suck

also the www called, they want your 1.6 for museum,   1.7 is far superior.....