Element A moves into contact with Element X due to Sponno advance. Since it is Element A move into contact rather than Element X, according to page 33 (Front Edge Combat) of the rules, Element A only suffers a -1 penalty in CC unless all of of its flank edge is covered by enemy Element Y. If Element A loses the CC, it will be destroyed since its flank edge is covered by enemy Element Y, no matter Element Y covers its whole flank edge or not.
In the situation of the left, Element A DOES NOT suffer a -1 penalty in CC since Element Y does not cover its whole flank. However, Element A will still be destroyed if it loses the CC.
Please also see page 40 of the DBMM Commentary - DBMM Page 38 - Comabat Outcome - Flank Edge Contact
Please also see page 43 of the DBMM Commentary - DBMM page 40 -Pursuing Elements - Moving Friendly Elements In Non-Standard Flank Contact With Elements Contacted By Pursuers