You observe the issue described in this article after you upgrade to ePO 5.10 (Build 2428) Update 9.

When you navigate to the Software Catalog, you see that:

• The option Hide older versions if not installed selected.
• Both ePO 5.9 and 5.10 are listed. Only ePO 5.10 is expected to be seen.

NOTE: Under ePO 5.9, it shows ePO Support Center Extension Update 3, incorrectly as version 5.10.0.434. The same details are also present under the ePO 5.10 Software catalog listing.