Virtuemart sometimes not charging tax

[YZF]

We have an intermittent problem with our website. 95% of the time the site works fine, however, once in a while we get an order processed that doesn't include the tax. Whenever I try to re-create the problem in Firefox or Explorer by adding the same products in the shopping cart, and selecting the same province for the address, the correct tax shows up in the shopping cart. I'm not sure if this is important but it was processed through Paypal. I am currently using Joomla 3.6.2 and Virtuemart 3.0.17.6. Has anyone else been experiencing this? Any suggestions on how this might be happening and how to fix it would be greatly appreciated.

[jenkinhill]

I am currently using Joomla 3.6.2 and Virtuemart 3.0.17.6.

Intermittent problems are very difficult to diagnose. Could be as simple as a very busy/overloaded server.

But did  you miss the vital security releases?
https://www.joomla.org/announcements/release-news/5678-joomla-3-6-4-released.html
https://www.joomla.org/announcements/release-news/5693-joomla-3-6-5-released.html
http://forum.virtuemart.net/index.php?topic=118683.0

[YZF]

Thanks for your reply. I will be updating to the newest version of Joomla etc really soon.

[YZF]

I am still having the same problem. I just had an order today with no tax (and another order where the tax was fine).

I am currently using Joomla 3.7.0 (was 3.6.5?) and Virtuemart 3.0.17.6. and PHP version: 5.6.30.

Any ideas why this might be happening? This was also a Paypal order if that makes any difference. Also, both recent orders where this happened, the customers were using Safari on a Mac laptop (Macbook).

Thank you for any help you can offer.

[GJC Web Design]

You really should be testing then using VM3.2.1..  (VM3.2.2 will be released very shortly)

I can't see paypal will effect anything as the totals are just passed to the payment plugin ... 

You need to describe your tax setup, your checkout (std. VM, 3rd party, OPC etc).. what the tax is dependent on

Some OPC are very ajax dependent and may get "confused" by constant changing of countries back and forth etc  or fail to update if the responses are slow or JS errors are present.

[YZF]

Thank you for the reply. We are in Canada, so each province has its own tax code and percent. Also, we are using RuposTel One Page Checkout.

We asked the same customer to re-do their order, and it went through with the tax just fine. You may have a point about the error being caused by a slow server as nothing had changed between the two orders.

Thank you for the advice on updating to VM3.2..., we will look into that soon.

[GJC Web Design]

Have u tried once your in the cart changing information e.g. states, addresses etc etc multiple times.. ?
Can throw up some oddities sometimes