The most likely reason is that you used the account inventory asset in a transaction, an adjustment, or a journal entry – you can not do that in QB.

Run the balance sheet, insure it is to accrual basis

click on amount for inventory asset
set the date range to ALL
click customize
Rows/Columns set […]

Resolution for 'account inventory issue: 'Why does my Inventory valuation and Balance Sheets not match for inventory assets? How do I fix it? Which is correct?' available: Yes.

The account inventory issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the account inventory issue yourself by looking for a resolution described in the article. If it is a complex account inventory issue or you are unable to solve the issue, you may contact us by clicking here or by using other account inventory support options.

For more information about resolving issues related to account inventory in Quickbooks/QBO or to get support for the issue 'Why does my Inventory valuation and Balance Sheets not match for inventory assets? How do I fix it? Which is correct?', click the link below: