SPARQL insert/delete with GraghDB randomly fails

I've been having issues with SPARQL insert/delete statements in my GraphDB database. I believe my queries are correct and they generally work. However, occasionally they inexplicably fail. The data seemingly becomes "locked" and immune to change via insert/delete query. I'm re-running the same insert/delete queries as more data are added to my database. Once an insert/delete query fails, the only way I can "fix" the database is to rebuild it entirely from scratch by re-ingesting turtle files. I'd really like to figure out this problem and find a solution. Below I've included two demo queries with identical where clause. Note that this particular insert/delete query has never worked, but I believe it should be functional.

Insert/delete query fails. "The number of statements did not change. Update took 0.9s."

PREFIX onto: <http://www.ontotext.com/>
PREFIX f: <https://redacted.org/term/>

# correct strain names

DELETE {
  ?sid f:strain_name ?strain_name .
  ?sid f:gisaid_strain_name ?gisaid_strain_name .
}
INSERT {
  ?gid f:strain_name ?fix_strain_name .
  ?gid f:gisaid_strain_name ?fix_gisaid_strain_name .
}
WHERE {
  ?sid f:strain_name ?strain_name .
  ?sid f:gisaid_strain_name ?gisaid_strain_name .

  BIND (REPLACE(?strain_name, "(A/swine/[^/]+/).+(A0.*)", "$1$2") AS ?fix_strain_name)
  BIND (REPLACE(?gisaid_strain_name, "(A/swine/[^/]+/).+(A0.*)", "$1$2") AS ?fix_gisaid_strain_name)

  FILTER REGEX(?strain_name, "A/swine/[^/]+/.+[^A-Za-z0-9]A0[0-9]{6,8}/.*") .
}

Select query shows hundreds of values that need to be corrected. Showing results from 1 to 987 of 987. Query took 1s.

PREFIX onto: <http://www.ontotext.com/>
PREFIX f: <https://redacted.org/term/>

# correct strain names

SELECT
  ?strain_name
  ?fix_strain_name
  ?gisaid_strain_name
  ?fix_gisaid_strain_name
FROM onto:disable-sameAs
WHERE {
  ?sid f:strain_name ?strain_name .
  ?sid f:gisaid_strain_name ?gisaid_strain_name .

  BIND (REPLACE(?strain_name, "(A/swine/[^/]+/).+(A0.*)", "$1$2") AS ?fix_strain_name)
  BIND (REPLACE(?gisaid_strain_name, "(A/swine/[^/]+/).+(A0.*)", "$1$2") AS ?fix_gisaid_strain_name)

  FILTER REGEX(?strain_name, "A/swine/[^/]+/.+[^A-Za-z0-9]A0[0-9]{6,8}/.*") .
}

Please let me know if I can provide additional information to help solve this problem. I'm fairly confident in the queries, but I don't know what else could be the issue.

Edit 1 - Fixed the mistake in the insert/delete query pointed out by @Stefan - brox IT-Solutions. At first this didn't seem to work. I was still able to query the data that should have been removed/changed by using the GraphDB browser GUI. I think the query result was being cached and that the cache result lasts X minutes post query. So waiting ~10 minutes (while writing a response) was enough time for the cache to expire and the actual query results to display. I'll have to keep these things in mind: 1) be more careful with copy/pasting between queries, and 2) don't spam queries through the GraphDB browser GUI.