Huge number of PHP errors

I’m seeing many Wordfence PHP errors in the error log.
Current PHP version is 5.6.40

As far as I can tell, Wordfence is still working ok, but here’s what the errors look like:-

Stack trace:
#0 /home/becomeab/public_html/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/lib/storage/file.php(254): wfWAFAttackDataStorageFileEngine::unpackMicrotime(”)
#1 [internal function]: wfWAFStorageFile->_getAttackDataRowsNewerThan(Resource id #27, 61195, 1412)
#2 /home/becomeab/public_html/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/lib/storage/file.php(1190): call_user_func(Array, Resource id #27, 61195, 1412)
#3 /home/becomeab/public_html/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/lib/storage/file.php(239): wfWAFAttackDataStorageFileEngine->scanRowsReverse(Array)
#4 /home/becomeab/public_html/wp-content/plugins/wordfence/lib/wordfenceClass.php(8097): wfWAFStorageFile- in /home/becomeab/public_html/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/lib/storage/file.php on line 921
[17-Jul-2019 12:02:28 UTC] PHP Fatal error: Uncaught exception ‘InvalidArgumentException’ with message ‘wfWAFAttackDataStorageFileEngine::unpackMicrotime $binary expected to be string with length of 8, received string of length 0’ in /home/becomeab/public_html/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/lib/storage/file.php:921
Stack trace:
#0 /home/becomeab/public_html/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/lib/storage/file.php(254): wfWAFAttackDataStorageFileEngine::unpackMicrotime(”)
#1 [internal function]: wfWAFStorageFile->_getAttackDataRowsNewerThan(Resource id #25, 61195, 1412)
#2 /home/becomeab/public_html/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/lib/storage/file.php(1190): call_user_func(Array, Resource id #25, 61195, 1412)
#3 /home/becomeab/public_html/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/lib/storage/file.php(239): wfWAFAttackDataStorageFileEngine->scanRowsReverse(Array)
#4 /home/becomeab/public_html/wp-content/plugins/wordfence/lib/wordfenceClass.php(8097): wfWAFStorageFile- in /home/becomeab/public_html/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/lib/storage/file.php on line 921
[17-Jul-2019 12:02:30 UTC] WordPress database error Commands out of sync; you can’t run this command now for query SELECT *, CASE
WHEN type = 3 THEN 0
WHEN type = 4 THEN 1
WHEN type = 7 THEN 2
WHEN type = 6 THEN 3
WHEN type = 5 THEN 4
WHEN type = 9 THEN 5
WHEN type = 8 THEN 6
WHEN type = 2 THEN 7
WHEN type = 1 THEN 8
ELSE 9999
END AS typeSort, CASE
WHEN type = 3 THEN parameters
WHEN type = 4 THEN parameters
WHEN type = 1 THEN IP
WHEN type = 9 THEN IP
WHEN type = 5 THEN IP
WHEN type = 6 THEN IP
WHEN type = 7 THEN IP
WHEN type = 2 THEN IP
WHEN type = 8 THEN IP
ELSE 9999
END AS detailSort

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