#items in cart not matching expected value for 'problem_user'

[pramam]

Bug found in automated tests on branch3-continueworking This branch was not submitted in the pull request.

User Account: problem_user
Likely related to issue #3.

In various tests cases, after adding X number of items to cart, it is found that the Cart Icon on top is showing a different number of items.
Test cases that reproduce this (on branch3-continueworking):
TestCase_3: Added 3 items to cart.
Expectation: To find 3 times in cart.
Actual: Found 2 items in cart.
Line in code that shows the error:
CartPage.checkNumCartItems: has 2 expecting 3 Error: CartPage.checkNumCartItems: has 2 expecting 3 at CartPage.checkNumCartItems (C:\pallavi\code\webdriverio\sdet-candidate-ui-pallavi-2\test\pageobjects\cart.page.js:36:19) at processTicksAndRejections (internal/process/task_queues.js:93:5) at async Context.<anonymous> (C:\pallavi\code\webdriverio\sdet-candidate-ui-pallavi-2\test\specs\checkout3.e2e.js:37:9)

TestCase_5:
Added 5 items to cart
Expectation: To find 5 items in cart
Actual: Found 3 items in cart
Line in code that shows the error:
CartPage.checkNumCartItems: has 3 expecting 5 Error: CartPage.checkNumCartItems: has 3 expecting 5 at CartPage.checkNumCartItems (C:\pallavi\code\webdriverio\sdet-candidate-ui-pallavi-2\test\pageobjects\cart.page.js:36:19) at processTicksAndRejections (internal/process/task_queues.js:93:5) at async Context.<anonymous> (C:\pallavi\code\webdriverio\sdet-candidate-ui-pallavi-2\test\specs\checkout5.e2e.js:37:9)

TestCase_6:
Added 3 items to cart.
Expectation: To find 3 items in cart
Actual: Found 1 item in cart
Line in code that shows the error:

Error: CartPage.checkNumCartItems: has 1 expecting 3
                    at CartPage.checkNumCartItems (C:\pallavi\code\webdriverio\sdet-candidate-ui-pallavi-2\test\pageobjects\cart.page.js:36:19)
                    at processTicksAndRejections (internal/process/task_queues.js:93:5)
                    at async Context.<anonymous> (C:\pallavi\code\webdriverio\sdet-candidate-ui-pallavi-2\test\specs\checkout6.e2e.js:36:9)```

[pramam]

On manual testing as problem_user, the cart count was checked. +1 means cart count is updated on clicking 'Add To Cart'. +0 means it did not update cart count as expected.

<style type="text/css"></style>

Cart Count	id of item
+1	add-to-cart-sauce-labs-backpack
+1	add-to-cart-sauce-labs-bike-light
+0	add-to-cart-sauce-labs-bolt-t-shirt
+0	add-to-cart-sauce-labs-fleece-jacket
+1	add-to-cart-sauce-labs-onesie
+0	add-to-cart-test.allthethings()-t-shirt-(red)