Sandisk Cruzer

[terry]

I use Plugin to download photos from cameras via card reader (via OTG) onto Nexus 7 (Android 4.4.4) and when Nexus storage low, copy to USB Flash Drive (via OTG) to free up storage. Worked ok with Verbatim & Lexar Flash Drives in March. In September used Sandisk Cruzer (16gb & 32gb) but they crash during file transfers requiring constant restarts. I then bought Kingstone Date Traveller 100 G3 Flash Drive overseas and I used this many times, with no problems to download photos.
Formatting Sandisks to Fat32, 8192, they still crash. Reformatting to Fat32, 4096 sectors and this worked the first time for data transfer. I disconnected & reconnected & then Sandisks crashed. I then reformatted Sandisks to ExFat, allocation units = 32kb. I can transfer files, disconnect, reconnect & transfer more files.
My questions:
1. Are Sandisk Cruzer (16 & 32gb) a known issue to you?
2. I saw that ExFat is experimental, what issues should I be aware of?