Unable to read xlsx files generated with Crystal Report

[snoob]

Hi,

When i try to read ($reader->open) a file generated with Crystal Report i got the following IOException :

could not open /tmp/xxxx for reading! (Index invalid or out of range)

After investigation, it works if i force the FileBasedStrategy by commenting this line(https://github.com/box/spout/blob/master/src/Spout/Reader/XLSX/Manager/SharedStringsCaching/CachingStrategyFactory.php#L65)
I have no idea why InMemoryStrategy doesn't work for my file.. Does anyone knows how FileBasedStrategy and InMemoryStrategy are different ? For me, they should work the same way it's only a performance concern.

Thank you by advance