Hi there anitasbookeeping,
It's great to hear that you clear your cache regularly. This is one of the best ways to make sure that QuickBooks Online will run optimally. Since you're still seeing the issue, I encourage you to try the following browser-related troubleshooting steps as well.
I know these each sound simple, but I've seen where even restarting a device can help sort out these kinds of strange issues. Additionally, you can try watching videos from other websites to see if you're running into the same issue. If you are, it may be worth contacting your Internet provider to learn what might be happening to cause these streaming issues.
If it's still only happening in QuickBooks, please don't hesitate to get in touch with us outside of Community. An agent will be able to troubleshoot with you one-on-one and our phone agents can even use a screen share tool to see what you're seeing. Here are the support options.
Phone and Chat: Click Contact Us to learn how to reach phone and chat support.
Schedule a Callback: click (?)Help in the upper right > click Contact Us > explain your situation > click Let's Talk > choose Get a callback (Note: Callback hours are the same as regular phone hours.)
Social Media: Facebook, Twitter, and Instagram from Monday to Friday between 9 a.m. and 8 p.m. ET
Wishing you the best!