Not sure if this is on Apple's radar or not, hopefully so. We have had a similar thing occur, and I found a workaround for it if the attachment can't be recovered by just resending from the iPhone or iPad, maybe someone else will know a way to fix or improve the method. Once received on a computer, it requires saving the email as an eml file and opening via text editor. Once opened in the text editor looking for the section that has the base64 encoded information for the particular attachment, you will find that the text is not actually encoded properly for just the particular attachment file such as:
--_007_2DBFBC07AE554C9FBBECACB7232533E8_
Content-Type: application/pdf; name="attachment.pdf"
Content-Description: attachment.pdf
Content-Disposition: attachment; filename="attachment.pdf"; size=531340;
creation-date="Tue, 17 May 2016 19:11:43 GMT";
modification-date="Tue, 17 May 2016 19:11:43 GMT"
Content-Transfer-Encoding: base64
Receivedfromsomewhere123123123123bymymailserver
234234234234withMicrosoftSMTPServerTLSid1432792Tue17May201613484905
00Receivedfromhostinformationbyp3plwbeout1503prodphx3secureservernetwit
hbizsmtpidvWoo1s0010FDBWt01WooAQTue17May20161148480700XSIDvWoo1s0010FDBWt01R
eceivedqmail8172invokedbyuid9917May20161848480000ContentTypemultipart/mixedb
oundaryf8c68204d8f2b879567551c3bf13eb7fXOriginatingIP199116157114UserAgentWo
rkspaceWebmail629MessageID201605171148462d72b9a84ca577e8313ec065200ea7849f4b
9d1ad8wbeemail15godaddycomFromsomesubjecttext
SubjectDataDateTue17May20161148460700ReturnPathmoreheaderdata
XMSExchangeOrganizationAuthSourcemail10mymailserverXMSExchan
geOrganizationAuthAsAnonymousXGFISMTPSubmission1XGFISMTPHelloDomainp3plwbeou
t1503serverGFISMTPRemoteIPIPIPIPIPXKSEAntiSpamIntercept
orInfoprotectiondisabledXMSExchangeOrganizationAVStampMailboxKaspersk5171608
00XKSEAntivirusInterceptorInfoscansuccessfulXKSEAntivirusInfoCleanMIMEVersio
n10f8c68204d8f2b879567551c3bf13eb7fContentTypemultipart/relatedboundaryc7a02.... .
Basically you can recover the corrupted attachment by selecting this readable text, and then finding in the output where you can not read the information any longer, you then remove everything from the Received text which starts what should be showing only base64 encoded data, to where the base64 encoded information actually starts:
It should be the last place in the file that has something like /pdfnameAttachmentADpdfContentDispositionattachmentfilenameAddachmentADpdf After this text it should start being valid base64 encoded information, deleting the garbage ahead of that after the correct heading info for the attachment and saving the EML file should result in being able to get to the non corrupted pdf attachment.
Content-Disposition: attachment; filename="attachment.pdf"; size=531340;
creation-date="Tue, 17 May 2016 19:11:43 GMT";
modification-date="Tue, 17 May 2016 19:11:43 GMT"
Content-Transfer-Encoding: base64
JVBERi0xLjQNJeLjz9MNCjQgMC
BvYmoNPDwvTGluZWFyaXplZCAxL0wgNTI0MjYxL08gNi9FIDQ3NTk1Ny9OIDEvVCA1MjQwNjcvSC
BbIDQ3NiAxNDRdPj4NZW5kb2JqDSAgICAgICAgICAgICAgICAgIA14cmVmDTQgOQ0wMDAwMDAwMD
E2IDAwMDAwIG4NCjAwMDAwMDA2MjAgMDAwMDAgbg0KMDAwMDAwMDY4MCAwMDAwMCBuDQowMDAwMD
AwOTMwIDAwMDAwIG4NCjAwMDAwMDA5NjMgMDAwMDAgbg0KMDAwMDAwMTA1OCAwMDAwMCBuDQowMD
AwMDAxNDE2IDAwMDAwIG4NCjAwMDAwMDM2ODAgMDAwMDAgbg0KMDAwMDAwMDQ3NiAwMDAwMCBuDQ
p0cmFpbGVyDTw8L1NpemUgMTMvUm9vdCA1IDAgUi9JbmZvIDMgMCBSL0lEWzxBMjdDMTMzMURGND
k0MjAxQUFGMzc5RDI3RUQxQzI2RT48MjQ1RDc2N0VCMkZGNERDOEFFMzA5RDI0OUREMUIzNjg+XS....
