The Bloomington Drosophila Stock Center has identified l(2)PC4-P41 (FBal0046038) as an allele of the zda gene. Kahsai et al (FBrf0237547) mapped the lethal in l(2)PC4-P41 to a six gene region ( 2R:18621522..18639268 ). Crosses to lethal insertions in the region reveal that l(2)PC4-P41 fails to complement Mi{Trojan-GAL4.0}zdaMI07788-TG4.0 (RRID:BDSC_77787). Whole genome sequencing reveals no changes to coding sequence with the exception of a conservative E186->D change also found in many DGRP and DGN 1000 genomes (so is unlikely to cause issues). 
A possible splice junction mutation was discovered in non-coding sequence:
C18631636->G 
This changes the 3' splice junction of intron 1 for the RA, RC and RD transcripts from: 
18631631-CTATGC-18631636
to
18631631-CTATGG-18631636
This may or may not affect splicing of these transcripts
This same change also affects the 3' splice junction of intron 1 for the RB transcript from:
18631636-CTTGGC-18631641
to
18631636-GTTGGC-18631641
Given this alters the largely invariant CT found at 3' splice junctions in Drosophila (AG for a 3' splice junction for a gene on the plus strand), it seems likely this will affect splicing of the RB transcript.