I’m using the most current beta (.10) in 12.8. Toad doesn’t save the last executed statement into SaveSQL.xml file. The size of file remains the original one (mine is 438 013 byte) , but the last modification always changes to the sysdate. Also an empty record created in View|SQL Recall: the connection string and the time of execution information are correct, but there is no visible statement for it.
My Editor|Code Assist|SQL Recall|Save only valid statements is on. The SELECT statement - which is executed in the Editor - gives a result set, with 2 rows.
In 12.7 there was an option how many statement should save to the SQL Recall file. I don’t know this option was deprecated in 12.8beta, but I didn’t find any option like this one. In Toad.ini SAVE_SQLS=1 and NUM_SQLS=500 are present.