Velocity themes are not working after LSV-658

• Type: Regression Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.0.X, 7.1.X
• Fix Version/s: 7.0.0 DXP FP93, 7.0.10.14 DXP SP14, 7.0.X, 7.1.10 DXP FP19, 7.1.10.5 SP5
• Component/s: Portal Services > Templates Engine
• Labels:
  • 7.0-blocker
  • 7.0.x-only
  • QA-FP
  • ee-ts
  • liferay-dxp-70-sp14
  • liferay-dxp-71-sp5
  • liferay-fixpack-de-93-7010
  • liferay-fixpack-dxp-19-7110
• Branch Version/s:
  7.0.x
• Backported to Branch:
  Committed
• Fix Priority: 4
• Last Working Version:
  7.0.0 DXP FP91
• Git Pull Request: https://github.com/liferay/liferay-portal-ee/pull/19938

Steps to reproduce

1. Create a Velocity based theme for Liferay 7.0 (to make it easier I've attached the one I'm testing)
2. Start Liferay with patch level fixpack-de-91-7010
3. Deploy your velocity theme.
4. Apply to one page.
5. Check that everything works as expected.
6. Stop the server and apply Liferay DXP 7.0 Security Fix Pack 202003 for Fix Pack 91
7. Start the server again

Expected behavior
Everything works as expected

Actual behavior
Velocity theme is broken and you can see, for example, how Velocity variables are not resolved. They are directly printed:
$theme.include($top_head_include)
$theme.include($body_top_include)
$theme.include($body_top_include)

Additional Notes

If you enable logs for org.apache.velocity category you'll see some extra useful information:
2020-06-22 07:30:36.397 DEBUG [http-nio-7080-exec-2][velocity:155] Null reference [template 'customer-theme_SERVLET_CONTEXT_/templates/portal_normal.vm', line 12, column 9] : $theme.include($top_head_include) cannot be resolved.
2020-06-22 07:30:36.397 DEBUG [http-nio-7080-exec-2][velocity:155] Null reference [template 'customer-theme_SERVLET_CONTEXT_/templates/portal_normal.vm', line 17, column 1] : $theme.include($body_top_include) cannot be resolved.
2020-06-22 07:30:36.398 DEBUG [http-nio-7080-exec-2][velocity:155] Null reference [template 'customer-theme_SERVLET_CONTEXT_/templates/portal_normal.vm', line 33, column 112] : $ProductNavigationControlMenu cannot be resolved.