IBM Mobilefirst 7 unable to make native function calls - ios

Question

I'm running an app, created using IBM MobileFirst 7, on iOS 8.4. At first it works fine: I can write to jsonstore and make other native function calls.
Then the application starts syncing and writing to the JSONStore (a lot of data) and it stops after a while (no errors in console). It usually happens while trying to call the WL.Client.invokeProcedure function.
I also noticed a strange behavior: if I double tap the home button it makes the next WL.Client.invokeProcedure call in the loop and I receive the results from the adapter but then it stops again (everytime I double tap the home button this happens). This also happens with other native calls (e.g. I tried to make a call to other native function in the JS console by using cordova and it only gets called after I double tap the home button).
Does anyone know what may be causing this behavior?~
EDIT:
Regarding the native calls: Since I'm using cordova, I can use a plugin to access some native functionality, example:
//this is what I meant by "native function calls"
cordova.exec(successCallback, errorCallback, 'SFRPowerSave', 'enable', []);
I'm not sure about WL.Client.invokeProcedure and WL.JSONStore functions, but I think they also use native code.
Here's what I'm doing:
//I get the first 50 dirty documents
function push(){
var numberOfDocumentsToPush = 50;
var dirtyDocuments = currentSyncStore.dirtyDocuments.splice(0, numberOfDocumentsToPush);
//then I call the adapter add method and return a promise
return when(WL.Client.invokeProcedure({
adapter : adapter.name,
procedure : adapter.push.procedure,
parameters : [ JSON.stringify(dirtyDocuments),
JSON.stringify({add: addParams}) ],
compressResponse : false
}, {
timeout: adapter.timeout,
invocationContext: {context: this, document: dirtyDocuments}
});
}
//after the promise is returned, I get the next 50 dirty documents and call the push function again, I usually have a lot of dirtyDocuments (lets say 10000).
//After a while it just stops, the WL.Client.invokeProcedure doesn't reject or resolve the promise and no timeout occurs.
//I can interact with the interface of the application but if I try to call some native function, it will not work (but it gets called immediatly after entering the multitask mode - double tap home button in ipad/iphone)
//In the adapter I call the stored procedure from the DB2 database one time for each document:
function pushLogs(logs, params, addFunction){
var parsedParams = JSON.parse(params);
var addParsedParams = parsedParams.add;
var addConfig = getConfig("logs", addFunction, JSON.stringify(addParsedParams));
var parsedLogs = JSON.parse(logs);
var globalResult = {
isSuccessful: true,
responses: []
};
for (var i = 0; i < parsedLogs.length; i++) {
var options = {
values : JSON.stringify(parsedLogs[i].document),
spConfig: addConfig
};
var result = invokeSQLStoredProcedure(options);
globalResult.isSuccessful = globalResult.isSuccessful && result.isSuccessful;
globalResult.responses.push(result);
}
return globalResult;
}

Answer 1

A PMR was opened to handle this question. It has turned out to be a Cordova defect and is now being handled via APAR PI47657: Application hangs when trying to call JSONStore asynchronously to sync data.
The fix will appear in a future iFix release, available at IBM Fix Central (as well as via the PMR opened).