Cart updating issues for some users

Some users have reported issues with the cart as follows:

1) Adding items to the cart does not affect the total at the top right of the page until you refresh the page

2) Removing an item from cart via the cart page results in an empty page until you refresh the page

Most testers didn’t experience these issues. So far three users have reported the errors; all are in the UK, and all reported that they occur across multiple browsers and devices. They are not all using the same ISP.

I’ve reverted to default theme and deactivated all plugins except WooCommerce but the problem persists.

Any ideas?

System report:

### WordPress Environment ###

Home URL: https://sanremobarnes.com
Site URL: https://sanremobarnes.com
WC Version: 3.3.0
Log Directory Writable: ?
WP Version: 4.9.2
WP Multisite: –
WP Memory Limit: 256 MB
WP Debug Mode: ?
WP Cron: ?
Language: en_US

### Server Environment ###

Server Info: Apache/2
PHP Version: 7.0.15
PHP Post Max Size: 20 MB
PHP Time Limit: 120
PHP Max Input Vars: 1000
cURL Version: 7.22.0
GnuTLS/2.12.14

SUHOSIN Installed: –
MySQL Version: 5.6.37
Max Upload Size: 20 MB
Default Timezone is UTC: ?
fsockopen/cURL: ?
SoapClient: ? Your server does not have the SoapClient class enabled - some gateway plugins which use SOAP may not work as expected.
DOMDocument: ?
GZip: ?
Multibyte String: ?
Remote Post: ?
Remote Get: ?

### Database ###

WC Database Version: 3.3.0
WC Database Prefix: wp_
MaxMind GeoIP Database: ?
Total Database Size: 22.03MB
Database Data Size: 20.18MB
Database Index Size: 1.85MB
wp_woocommerce_sessions: Data: 0.02MB + Index: 0.02MB
wp_woocommerce_api_keys: Data: 0.02MB + Index: 0.03MB
wp_woocommerce_attribute_taxonomies: Data: 0.02MB + Index: 0.02MB
wp_woocommerce_downloadable_product_permissions: Data: 0.02MB + Index: 0.05MB
wp_woocommerce_order_items: Data: 0.02MB + Index: 0.02MB
wp_woocommerce_order_itemmeta: Data: 0.05MB + Index: 0.03MB
wp_woocommerce_tax_rates: Data: 0.02MB + Index: 0.06MB
wp_woocommerce_tax_rate_locations: Data: 0.02MB + Index: 0.03MB
wp_woocommerce_shipping_zones: Data: 0.02MB + Index: 0.00MB
wp_woocommerce_shipping_zone_locations: Data: 0.02MB + Index: 0.03MB
wp_woocommerce_shipping_zone_methods: Data: 0.02MB + Index: 0.00MB
wp_woocommerce_payment_tokens: Data: 0.02MB + Index: 0.02MB
wp_woocommerce_payment_tokenmeta: Data: 0.02MB + Index: 0.03MB
wp_woocommerce_log: Data: 0.02MB + Index: 0.02MB
wp_commentmeta: Data: 0.02MB + Index: 0.03MB
wp_comments: Data: 0.02MB + Index: 0.09MB
wp_gallery_galleries: Data: 0.00MB + Index: 0.00MB
wp_gallery_galleriesslides: Data: 0.00MB + Index: 0.00MB
wp_gallery_slides: Data: 0.00MB + Index: 0.00MB
wp_hugeit_slider_slide: Data: 0.02MB + Index: 0.00MB
wp_hugeit_slider_slider: Data: 0.02MB + Index: 0.00MB
wp_huge_it_reslider_sliders: Data: 0.02MB + Index: 0.00MB
wp_huge_it_reslider_slides: Data: 0.02MB + Index: 0.00MB
wp_hustle_modules: Data: 0.02MB + Index: 0.03MB
wp_hustle_modules_meta: Data: 0.05MB + Index: 0.03MB
wp_jckwds: Data: 0.02MB + Index: 0.00MB
wp_links: Data: 0.02MB + Index: 0.02MB
wp_optins: Data: 0.02MB + Index: 0.03MB
wp_optin_meta: Data: 0.02MB + Index: 0.03MB
wp_options: Data: 3.48MB + Index: 0.06MB
wp_postmeta: Data: 1.47MB + Index: 0.63MB
wp_posts: Data: 14.41MB + Index: 0.27MB
wp_smush_dir_images: Data: 0.02MB + Index: 0.03MB
wp_termmeta: Data: 0.02MB + Index: 0.03MB
wp_terms: Data: 0.05MB + Index: 0.03MB
wp_term_relationships: Data: 0.02MB + Index: 0.02MB
wp_term_taxonomy: Data: 0.05MB + Index: 0.03MB
wp_usermeta: Data: 0.02MB + Index: 0.03MB
wp_users: Data: 0.02MB + Index: 0.05MB
wp_wc_download_log: Data: 0.02MB + Index: 0.03MB
wp_wc_webhooks: Data: 0.02MB + Index: 0.02MB

### Post Type Counts ###

acf: 1
attachment: 92
block: 5
chef: 3
custom_css: 7
customize_changeset: 31
food_option: 3
nav_menu_item: 174
news: 4
page: 56
pjc_slideshow: 2
popup: 2
popup_theme: 6
post: 9
product: 87
product_variation: 38
revision: 558
ris_gallery: 2
shop_order: 15
testimonial: 6
wccpf: 1
wpcf7_contact_form: 3

### Security ###

Secure connection (HTTPS): ?
Hide errors from visitors: ?

### Active Plugins (1) ###

WooCommerce: by Automattic – 3.3.0

### Settings ###

API Enabled: ?
Force SSL: ?
Currency: GBP (￡)
Currency Position: left
Thousand Separator: ,
Decimal Separator: .
Number of Decimals: 2
Taxonomies: Product Types: external (external)
food (food)
grouped (grouped)
simple (simple)
variable (variable)

Taxonomies: Product Visibility: exclude-from-catalog (exclude-from-catalog)
exclude-from-search (exclude-from-search)
featured (featured)
outofstock (outofstock)
rated-1 (rated-1)
rated-2 (rated-2)
rated-3 (rated-3)
rated-4 (rated-4)
rated-5 (rated-5)

### WC Pages ###

Shop base: ? Page not set
Cart: #2518 - /cart/
Checkout: #2519 - /checkout/
My account: #11 - /my-account/
Terms and conditions: ? Page not set

### Theme ###

Name: Storefront
Version: 2.2.7
Author URL: https://woocommerce.com/
Child Theme: ? – If you are modifying WooCommerce on a parent theme that you did not build personally we recommend using a child theme. See: How to create a child theme
WooCommerce Support: ?

### Templates ###

Overrides: –

The page I need help with: [log in to see the link]