diff --git a/src/etTran.cpp b/src/etTran.cpp
index dcae40f96..aa2c3e4a6 100644
--- a/src/etTran.cpp
+++ b/src/etTran.cpp
@@ -1242,7 +1242,7 @@ List etTrans(List inData, const RObject &obj, bool addCmt=false,
     } else if (lastId != cid) {
       lastId = cid;
     } else if (lastTime > ctime) {
-      if (inEvid[i] != 3 && inEvid[i] != 4) {
+      if (!hasEvid || (inEvid[i] != 3 && inEvid[i] != 4)) {
         isSorted = false; // The prior EVID=3 w/reset a reset time
         // REprintf("\t not sorted");
       } else if (lastTime > ctime) {
diff --git a/tests/testthat/test-etTrans-780.qs b/tests/testthat/test-etTrans-780.qs
new file mode 100644
index 000000000..d7e71ee88
Binary files /dev/null and b/tests/testthat/test-etTrans-780.qs differ
diff --git a/tests/testthat/test-etTrans.R b/tests/testthat/test-etTrans.R
index dbe8ac90b..cc34eccc8 100644
--- a/tests/testthat/test-etTrans.R
+++ b/tests/testthat/test-etTrans.R
@@ -1379,3 +1379,71 @@ d/dt(blood)     = a*intestine - b*blood
     expect_equal(tmp$II, c(24, 0, 0, 0))
   })
 })
+
+
+test_that("warning on translation (#780)", {
+
+  p <- test_path("test-etTrans-780.qs")
+  skip_if_not(file.exists(p))
+  dat <- qs::qread(p)
+
+  m <- rxode2parse("
+    param(Kpm_pop, V_pop, k_pop, k12_pop, k21_pop, ka_pop,
+          km_pop, a1_Cp, b1_Cp, a2_Cm, b2_Cm, omega_Kpm, omega_V,
+          omega_k, omega_k12, omega_k21, omega_ka, omega_km)
+    cmt(depot)
+    cmt(central)
+    cmt(cmt2)
+    cmt(cmt3)
+    Kpm = exp(Kpm_pop + omega_Kpm)
+    V = exp(V_pop + omega_V)
+    k = exp(k_pop + omega_k)
+    k12 = exp(k12_pop + omega_k12)
+    k21 = exp(k21_pop + omega_k21)
+    ka = exp(ka_pop + omega_ka)
+    km = exp(km_pop + omega_km)
+    d/dt(depot) = -ka * depot
+    d/dt(central) = -k12 * central + k21 * cmt2 + ka * depot -
+      k * central - Kpm * central
+    Cp = central/V
+    d/dt(cmt2) = +k12 * central - k21 * cmt2
+    d/dt(cmt3) = +Kpm * central - km * cmt3
+    Cm = cmt3/V
+    y1_Cp = Cp
+    if (CMT == 5) {
+      rx_yj_ ~ 2
+      rx_lambda_ ~ 1
+      rx_low_ ~ 0
+      rx_hi_ ~ 1
+      rx_pred_f_ ~ y1_Cp
+      rx_pred_ ~ rx_pred_f_
+      rx_r_ ~ ((a1_Cp) + (rx_pred_f_) * (b1_Cp))^2
+      ipredSim = rxTBSi(rx_pred_, rx_lambda_, rx_yj_, rx_low_,
+                        rx_hi_)
+      sim = rxTBSi(rx_pred_ + sqrt(rx_r_) * rxerr.y1_Cp,
+                   rx_lambda_, rx_yj_, rx_low_, rx_hi_)
+    }
+    y2_Cm = Cm
+    if (CMT == 6) {
+      rx_yj_ ~ 2
+      rx_lambda_ ~ 1
+      rx_low_ ~ 0
+      rx_hi_ ~ 1
+      rx_pred_f_ ~ y2_Cm
+      rx_pred_ ~ rx_pred_f_
+      rx_r_ ~ ((a2_Cm) + (rx_pred_f_) * (b2_Cm))^2
+      ipredSim = rxTBSi(rx_pred_, rx_lambda_, rx_yj_, rx_low_,
+                        rx_hi_)
+      sim = rxTBSi(rx_pred_ + sqrt(rx_r_) * rxerr.y2_Cm,
+                   rx_lambda_, rx_yj_, rx_low_, rx_hi_)
+    }
+    iwres = (DV - rx_pred_)/sqrt(rx_r_)
+    ires = DV - rx_pred_
+    cmt(y1_Cp)
+    cmt(y2_Cm)
+    dvid(5, 6)
+  ")
+
+  expect_warning(etTrans(dat, m), NA)
+
+})